Houdini Lighting & Rendering Overview for Maya Users

hello so this is going to be a video on houdini lighting look dev and rendering for my users this is a very quick overview i'm just trying to throw out all the information that i wish i knew when i first had to use houdini i'm primarily a my user but there are numerous jobs over the years where i've had to use houdini for lighting and rendering so i set up this quick example scene i'll quickly cover everything that i think is necessary there is much more to it houdini is a bit more complicated but i'll just cover the things i think are necessary timestamps will be in the descriptions below so feel free to just jump and use that because i don't know how long this video will be and yeah let's let's jump right in so in the scene so far um so when you open up houdini the controls will be similar to maya so when you hold down alt and left left click then you can rotate around the focal point and alt hold down right click and you can zoom in and out and then alt with middle mouse shifts around and spacebar and f that focuses on whatever is selected so nothing is selected so it was doing that to the center of the origin spacebar and h that resets actually on the bottom of the screen you can probably see it says home home c plane so that's basically resetting so if you have any camera clipping plane weirdness going on maybe press ctrl h with your scene or you could press d and go to view and then you can actually change your near and far clipping planes this is something that you know is more well known in maya how to fix where it is okay so on the yeah on the top menus you've got all the different things it is very much like maya but you don't you know so you could just click around there and search for things otherwise in the right hand side you've got your main menu which is the object menu so you can with all these menus you can hit tab and you can search to create something so in the object menu this is where you would put a camera you know so if you're doing a vfx project this is where you would create a camera or import an alembic camera so in fact you would probably search for alembic so i hit tab and just search for alembic something like that if you want to create primitive objects you know you can search for a sphere or a cube let's just do the sphere for the moment and then i hit enter select and what it does is it creates a geometry node and then you double click on that and this is where the actual sphere is i cannot see the sphere so i've just selected this and i'll press spacebar and f and it finds the sphere for me on the right hand side we have these different options so you've got light normal lighting or shaded textures on that's pretty much all you need if you want to go to your render camera let's say you've got a render camera actually let's create another camera so i've gone back i went back and menu there so object is pretty much the main menu i'm going to hit tab search for camera whoops um okay so we've got camera one so let's say i want to render something or i want to move my camera in a more dynamic way so what i can do is here i can select camera and i can press this lock and what this means is now if i move around in this view it's actually moving the location of this camera so i'm holding alt and holding down right click at the same time and now middle click just to shift around and then i can unlock so now when i zoom out you'll notice it says no cam because i've unlocked it now the camera is there so i've not affected it the good thing about that is it means when you go back to your camera if you um you know by accident um moved it doesn't actually affect your camera position so that's that's pretty neat thing that it does as well so with objects with the object menu in houdini what happens is whenever you import an object or geometry you get a geometry node and here is where you can make adjustments so let's say this sphere by the way is pretty much a nurbs object so if we want to put any textures onto it we would have to convert it into polygons so i hit tab search for convert so let's say that's what we want to do and you'll notice this is blue and then purple the purple means it's going to render that and the blue is the visible so let's let's shift that down and you can see after the conversion we now have a pretty harsh looking sphere so then we can actually change the amount of divisions let's just put 20 20. it's pretty smooth pretty smooth okay that's great and another alteration generic one you could do is transform so i hit tab search transform [Music] and then connect that up and let's view we want to see it and i hit um [Music] go to the cursor a bit oh if you select a node in the object area and nothing's happening move your mouse to the scene view and hit enter and then it will actually give you the parameters of what that node is related to if that makes sense so transform i nothing happened but when i hit enter it actually gave me the ability to now transform my sphere okay so i can go to my camera view so cam cam one and i can actually change you know some of the stuff to do with my sphere so we've got the hot keys e uh sorry w w is for shaded and wireframe e scale r rotate and t is move so i could actually just scale this up a bit for our camera and there we go in some companies they add a null at the end you can also use nulls for scaling as well maybe not in this menu but in the uh in the main object one so outside of the geometry area it's not uncommon to see because of the scale differences if you're modeling stuff in maya you might have to change the uniform scale to something like zero point um i think it's 0.1 i forgot the support the scale differences are but for example if you're importing a lot of assets from maya and the scaling is um you know 10 times bigger then you can essentially just do this on a null and then start connecting up all your objects to that one now and easily scale everything as well cool also uh something that is very typical is when when you're creating objects to be rendered at least in vfx projects you would name it and then put render after it so for example this is i'm going to call this ball underscore render and that's just to remind you that you in the render area you need to put in this object to render okay so we've got a camera and we've got uh object so we need to create a render node or a rop basically so i go to the out area so we've got the the main ones that you'll need to pay attention to everything else you pretty much ignore to be honest object this is where you make objects and cameras out that's where you do your rendering and mats that's where you do your materials however it's not always where you do your materials so just to add a bit of confusion because this is a general area where you do materials but but what you can do is have self-contained materials which is great because let's say you've got a complicated scene you've got this stuff going on and you've just been focusing on one asset and your friend says or colleague whatever they say oh yeah can you just sort out this ball render what you can do is you can actually self-contain the shader by going in here typing in matte sorry material and create a material network and then i double clicked on that so now i could put shader in here and it will be contained within this ball render node which is pretty cool i've just realized we don't have a material so i should just say if you hit tab search material there we go you can actually just apply a material here there is no group because this is just a single object polygon that we converted to a polygon so we can just put a shader in there as an example in the matte net i'm going to hit tab let's search for principles so i'm using by default our houdini uses mantra so principal shader is mantra so let's just make this color red we go and i can call it ball underscore ps for principal shader keep in mind these are multipliers so this the base color here they're all 0.2 to start with so if you are importing a base color texture you want to put them all to one so pure white because this is a multiplier and the same goes for roughness as well because if you're putting in a roughness map then this is actually reducing it it's already having an impact which i i personally think is quite stupid so i don't i don't know why it's set up like that what else you know if you want to import textures you do it in the textures tab keep in mind that mantra if you're using it primarily works with dot rat files so if you create textures in substance let's say substance painter and you export them as tiffs then it's i it's a good idea to convert them to rats so you can get scripts online to do that but if you do that in houdini you would have to go to render mplay load disk files and then wait for some reason it takes a while to load and then find your textures so there we go there's one texture and then you would have to go file save frame as and then name it and then at the end put dot wrap so for example i i dot rat and then i hit enter and you see it changed some of this stuff and then you click save i'm not going to click save because i don't want to overwrite anything there we go that is one rap file the thing is because houdini is going to convert it to a rat when you try render anyway similarly to arnold's converting to tx files i don't think rats are mipmaps like arnold you know mipmap is an image format which has different iterations of the resolution so it's like versioning um but anyway you know if who if mantra is going to convert them anyway when you've got a lot of textures you want to remove any conversion time basically so it's a way of optimizing anyway it's up to you to do that so if you want to load in textures you would do it here you turn on use texture and yeah just remember what i was saying there so if you are putting in textures put the roughness to one so it's reading that full roughness and then put your base color all that stuff to one as well with metallic it doesn't it doesn't really matter if it depends if your object is metallic or not if you are putting in a metallic map metalness map i should say and you want to put it to one so bump and normals as well this just put your normal map in here don't put a bump in so you click enable just put in your normal map there as a dot rat as well for displacement um you could put in your height map from substance or if you actually have painted in mari a displacement map then you would put it in here and load it in there and something to be aware of is what you could do as well if you want it to be a bump map you can load it in there change this offset to zero and then turn off true displacements and you will have a bump map so there we go and that is all self-contained within this object because you can see these different levels so what we started with we created the ball node sorry we created the sphere which created this geometry node and then we started to do things in here so we converted its polygons we transformed it for the camera and then we created material and then we can apply to this material um yeah i click here here and we can find the object and because we've created this matte net we can actually find the shader it's all self self-contained so if anyone needed this in their shot or in their project then it's very easy to you know pass it on as well rather than just everything being in the mat area as well so we've accepted that and now has been applied cool and what else oh yeah with within the shaders so you saw how i imported everything initially when when i did stuff in houdini i would do it the maya way which is create a texture as an example and if you're doing look dev you know you might add in color correct and then you go okay so i want the color to go to there and then i do a color correct to lift that up and then the color back out you know you might you know will that work yes but is it um are there any cons to it yeah it can be a bit more buggy and slow things down in the long run it's better to just do these sort of changes internally within you know within the shader it depends on the size and scale of your project so typically i was taught i was always told to do it within the shader i have tested it both ways and i've got the same sort of result but you know if people that use houdini every day for decades if they're telling me to use it within the principal shader then obviously i will do that um when you hit tab there are other things that you can use so standard um thing i use a lot is clamp so you see that we've got a roughness input somewhere so yeah just making you aware that some of the same stuff you have in maya will be within houdini so let's try jump in here but when you do that because the node is not unlocked you'll get this message coming up basically so what we need to do is unlock this shader to in order to get inside it so we right click and we do allow editing of contents i'm just going to disconnect this bit here so what i can do is hold down y and you get scissor symbol and you can actually draw a line and then when you release it'll cut any connections that's pretty cool so now that we've unlocked the shader when we go inside you see there's a lot a lot of craziness to make this area bigger i can hold down control and press b basically this is just all the inputs so i don't need to know 100 what's going on i just need to find okay base color so you know imported the texture this you would do in my experience you would only really go into this if you're just doing some form of look deving so for safety i would make a null so i hit tab search no and the idea is just we can see all these connections going into the color and we don't want to destroy that we just want to neatly put them into this one line otherwise you know you could you could end up breaking a shader and then you could put in your color corrects or your color mix color makes very cool mode because what you could do with the color mix is before i plug it in you can see you've got bias amount and secondary color so what this means is what you could do is you drop in a color mix and if you want a different um [Music] like texture being blended then you can actually plug in in the bias that's where you can put in your transparency map for the second texture and then in secondary you could get a different picture so as an example um dirt like you could create a procedural pattern and you could put it into the bias as a cutaway and then secondary color so you could just pick a constant if you need a secondary color actually maybe not constant um [Music] actually you could pick colors with inside there okay so second color for now is a purple i don't know why let's say dark red so that would be a secondary color and then in the bias mount so if i rendered this now it would be 50 dark red versus 50 um actually they're both red i think in the in the actual shader didn't i make the color red i did yeah okay there we go anyway that's just an example so let's jump back in and if you change your mind about any of these nodes but you're not sure about deleting them you can select them and then you can go to this area which is bypass so it doesn't delete them but it just just bypasses them so simple enough okay let's let's make it smaller holding ctrl and tap b now it's smaller okay so creating lights let's quickly cover that you could see i've got this camera clipping problem so i'm going to press spacebar and h and now it's reset so it's solved that issue okay let's look at this goblin character how did i import this so the way in which i created this this goblin setup was i got the alembe i exported an alembic from maya so i renamed everything in a nice way and when you import an alembic in that manner in order to get the groups and naming from my you need to go to primitive groups and change it to name group using transform node full path remember when you export alembic to turn on in settings write uvs and world space if you put in a particular load location you need to do that as well and then with inside there when you click um when you load an alembic so i'm pressing this visibility just to display it you could press i this is where you get information about what is coming in so we see all these different groups it's saying we've got 15 primitives in there which is cool so it means it's loaded correctly you can see what i've named all these different areas and that's also important because we can use things called wild cards which basically just for example the word eyeball if we want to select just the eyeballs we can just type that phrase put an asterisk at either end and then it will just select those so a good way in which to separate these and control them bit more is to use group create so hit tab search group create and then you would plug that in and then within there what you can do is you can click on this base group and it will come down with the geometry so what you could do is just pick one one thing but that's created a very specific path which is good and bad because if you change the model in maya and rename it it won't necessarily pick up the same model so that's kind of good and bad but what you could do is as i said earlier you can press asterisk and search the word eyeball and hit asterisks again hit enter that is a wild card so now when i view here you can see the eyeballs are highlighted and when i go to display group and attribute list you see the uh highlighted yellow there as well so that's worked and it means if we go if someone goes back to maya and they change it and the name of it changes from what is it called eyeball unscored g01 let's say it changes by accident to eyeball until geo three if because we've got this uh wild card then that won't matter it will still pick it up so when we reload when we select the alembic and then reload from whoever's altering the model it'll still be fine we could also use a blast node a blast node can be destructive and i'll explain why um actually i was just about to show you the way which is not destructive okay let's okay as an example i've got my alembic selected so i'll select the head and then hit delete and you'll see it creates a blast so it's deleted the head and it just says 14. so it's picked that group of vertices and it's just removed them and the thing is when the model if it gets updated and any point or changes then this blast node can be defunct so it'll stop working so if you start doing stuff like that or separating things because you can you can also use this blast node although i hit delete i could also do the inver uh inverted version of that so i could i could use it to isolate that selection so if i wanted to apply a shader just to that head what i could do is i could blast it out and then type material and then i could plug that in and then i could do copy and paste that and then invert it and then merge the results hit merge so i could you know blast the head out and then blast the eyes and everything else out and then put a material on one material on the other and then merge together seems logical but because i've just done it in such a destructive way it's yeah it's gonna become unstuck you never know when you might change a model so the group method i think is good you can also use groups within a blast so i'm just making you aware of that when you delete something as well so the way in which i've done it for this particular setup is i've done the group create and then i put in the wild cards i also changed you change these as well just to something that you can pick up later down the line so i did it for all the separate parts of this character so for the rings i'm just gonna select them just so you can see the wild cards i'm using but as you can see as well it's you can see what it's picking up so i just did a wild card hair and it picks up all these different things like that is so convenient it's very cool so the material node then what you do is you can use the groups to apply specific shaders so you can create i'll create another one there so i press the plus or you can delete doing that so you click on the group so all these are the ones that are from maya the my groups coming straight from the olympics and these ones here are the ones that i just created upstream so just above everything else then i can pick i just want the i pupil underscore group and then you can pick your shader and because it's self-contained within this goblin underscore render node i can just pick oh i want you know the pupils to be gold so there we go so when i render that they will be gone but i don't want that actually that sounds terrible okay so i've done this and then i applied i did this for each of them let's jump inside the shader so what i've done is i've made these different shaders in fact gold the gold one is just a default one so if you want to use if you want to use the default shaders within houdini but you want it to be within your self-contained object what you could do is go to the material palette and you can see down here we've actually got this object goblin render goblin mat net so we can scroll down let's say we want rough glass so we can actually put it into our self-contained object and then when we go back to the mat nat you can see it's just appeared here so now we have we have rough glass self-contained within our object so it's more you know a sort of organizational type of thing okay so in terms of the look deving and stuff like that so with each of these objects you go inside the shader and you can see i was actually there's quite a lot of stuff you can you could play around with but here's an example i'm actually bypassing it but believe what i was talking about earlier with primary and secondary colors i was doing a test with the base color so what i had was the original texture going in as a primary color and then the bias was so basically the the map that i wanted to select what was appearing and what was not i was using a curvature mixed with noise so i was picking um so the dark areas the shadowing areas of the object basically um uh what's i'm trying to think of a good way to explain this basically the crevices and creases and wrinkles of the character i basically wanted to exacerbate the color so make it darker and then make it lighter so if i go to this color correct here so i've got the diffuse um or base color and then you can see i turned the value up there and the color correct and then that's plugged into secondary so what was happening here in my test was i was making the higher points on the character like the ridge of the nose and you know just nowhere inside wrinkles i wanted to make them brighter to exaggerate the look but you could also see i bypassed this so it means i got to a point where i thought actually this is rubbish but just shows you what you what you can do you know that's using a curvature then i'm using turbulent noise and then also a rest position because otherwise otherwise these will move i believe they're 3d 3d noises or something like that it's not quite the same as using um using a noise within my sort of different different game we're playing okay so that's how i connected everything up there i'm going to press ctrl b and let's go to the object area so i've got got the render camera in there this is where you can set up your resolution icon scale that's just the size of the camera in the viewport so i'm pressing spacebar f to zoom onto this um so yeah we could pick the resolution the focal length if you want a background image appearing so if you've got footage if you're doing a vfx shot and you've got footage you might want to load the background image just to you know if you're trying to line something up or if you've got some reference um that's pretty much it for the render camera in terms of lights let's uh let's make a new one so i've got i do have all these lights here and these are actually all constrained to this now i love constraining lights because i just find it super useful really okay so the only things you really need are you just need an environment light so this would be your hdr and to find these if you hit tab search light so a light is just the generic one and you can change the settings inside so if you want an area like a spotlight that sort of thing you can change it within that standard light and then the environment light that is what would be your hdr or image based light so when you create an environment light you will get something like this so you can see i've put in some hdr that i got off of the internet and then i lowered the exposure and that was pretty much it and then for this rim light which you can see here intensity by default is one and then exposure is 11 and i change the type i think by default the type is point so i changed it to grid so if you want to see the light you want to turn on render light geometry and then change the area size as well [Music] there are a few other general options i mean if you've used mine before it's self-explanatory some of these options will only affect the type of light you pick as well so that's something to keep in mind um but aside from that one thing that um might be of use is actually the shadow mask so if you don't want an object to be affected by a light then you can see in the shadow mask this affects all of your lights as well and there's an asterisk there so that selects everything so this light is affecting all the objects so if we want it to not to not affect one object so let's say the eyes eyeballs for some reason then we could actually click there oh actually no it's uh it's object based okay so let's say we don't want the ball to be affected by that light or cast shadows because of that light we would select that ball and when we click accept shadow pattern it means this light is going to affect all these objects there so it's kind of like light linking pretty much but what i want is to just reset that so i'll just put the asterisk back there so you've got that same option with all these lights as well if you want to constrain a light because if i select one of these and press uh t and then move it you'll notice it starts to bend if you would like to do that with the light search tab i'll make fresh one and i'll change from type to grid so this is an area light sampling quality actually it says in the description there that it's for area lights and sunlight so keep that in mind so i primarily use just uh area lights it means you can just improve samples per um per light rather than you know put up all your multiplier samples you know so let's put this on 100 by 100 just so we can see it okay so it's there and what we could do is to create the constraint we can go to constraint make sense and you can see this funny little picture of some eyes and you click on look at and you see the bottom of the screen we have a prompt that says now select at can't read now select look at object if any press enter to accept selection so i'm not going to select anything i'm going to hit enter hit enter again and you'll see it's just loaded up something there we can see there's a null and there's a look at and get world space so if i just jump back and we will see there is now a new null null 3 so to avoid confusion i should probably rename these but i'm just going to prove a point for a second you see it as i move this now the light now faces that particular direction so then you could name this um fill o2 should probably add light at the end and then you could call this fill unscoro2 [Music] constraint something like that it's pretty much what i did with the character and then i just put this thingamajig this null inside and then i moved the light around i did that for all three of them as well so yeah that's pretty useful little thing so i'm going to delete those because i don't actually want that so let's jump to the render settings so where you actually do the rendering and setups so you go to the out section and you create a thing called a rop which is the shape um sorry the render the render node basically so if you want to create one type in hit tab type mantra there you go you have one but because i've already got one i'm just gonna talk about it briefly so within here you would select your camera and the resolution is inherited from your camera if you remember when i clicked on the camera earlier it had the resolution which was half hd inside your render sorry inside your wrap this is where you can do for test renders you can override the resolution you can turn on your motion blurring by default it's probably on the image tab so you want to pick your output location within houdini dollar f4 is frame range as well so it's kind of like in nuke where you've got percentage d that is image sequence and four hashes as well that could be used to signify an image sequence as well so what else we have the default these like avs like render passes the default ones in this extra image planes tab so you can see i've turned on a few personal favorite is combined lighting per component so that's going to separate the lights out that's why i was talking about sampling light sampling because i like to separate the lights and then see which one if there's one causing particular issues then at least i can turn up samples with one surface spec rough sorry surface specular roughness that will basically show you your roughness map and you can see here i actually added an extra image plane which was for the light separations as well because these these are the default ones there as well but sometimes i think um at least for the combined lighting per component it was not working earlier so i pressed plus so it adds an image plane which is a render pass and then you click here and then you've got this list down here so then i found it combined lighting per light and you can see there but i'm going to delete that because i don't i don't need that i've already got it um what else you've got extra settings crypto mat if you're familiar with maya you would be aware of what is going on there and then for rendering you've got pixel samples this is basically like the aaa samples in maya for arnold so this is all the uh overall multiplier i should say then you've got min min and max ray samples so this is kind of like adaptive sampling so it's saying this is the maximum multiplier for the raise noise level this is like thresholds within arnold i think it's called threshold or yeah pretty sure that's right but anyway the lower this goes this number the more variation or um the clearer basically the noise will be but you have to marry up between these two areas like the amount of samples you use because you could you could put this pixel samples to 10 by 10 which is a lot but then this could also be on point a so nearly one so your render would probably still look pretty trash because there's not enough variation like these um it's just giving the computer more time to look at the different um how two pixels relate to each other basically and then you have the general overrides for subsurface quality you know all this stuff is pretty self-explanatory if you've used it before render limits as well um the main one that might be relevant to your scenes probably the refract limit sometimes if you've got a lot of refraction occurring you might end up just rendering black instead of see-through that's because the ray limit has reached its max distance so you might have to increase that that's something that happens in maya what else tile size uh i normally reduce that when i use my or houdini just because when you when you go to render view to render so you'll notice these little tiles pop up and that's just saying that's just the size at the area size that the that your computer will look at so you have to you have to find a sort of um what's this phrase like a good a good point basically because if they're too big then your computer like if if i made this number bigger and my computer might take hours just to render this big chunk whereas if i break it into smaller pieces then it would give it could just optimize the render speed pretty much saying that if you put the tile size to one then you're pretty much where you started like it won't particularly help okay so i think we've covered everything the render settings the object so now you can make an object put it into a scene so we've got the goblin important alembic from maya and then we created groups separated the groups um whoops so we imported the alembic and separated the groups remember to use this display group and attribute list so this is quite a clean way we use wild cards to do that we made a material network created shaders inside there did some look deving inside one of them at least the goblin shader so we did that and using a material node we selected groups and then assigned shaders to specific groups and then we looked at lights as well so we talked about that and then we also covered how to make a constraint for a light and then we ended with setting up this uh this wrap as well selecting the render camera and this is what the end render looks like so i've let it render for a few minutes now but i don't need to hit finish it's not an amazing render to be honest but let's just look quickly look at the passes that have come out so you can see it's pretty much like mine you can use this drop down there is also another another menu here where you can change um the exposure and stuff like that and then reset it and then look at the alpha rgb you know that sort of thing so let's look at all subsurface so you can see subsurface uh pass on its own subsurface color so this is when the rays here and um what the color that's bouncing around basically when the rays penetrate and then the specular roughness i think there was a bit of color correction for that and then the separated lights that's pretty cool actually so you can see the subsurface scattering by the way clicking down on a certain point that makes the computer render that particular area i can't remember if my does that i haven't used mine for a while now and then the top light that looks pretty freaky actually i feel like not so freaky hdr pretty flat but then all combined there we go but by separating the lights at least we know okay we can turn up the samples in one because they're all apart from the hdr they are all areas anyway anyway i hope that has been use um useful to anyone like any of my users pretty much i thought i would just summarize everything that i found useful when trying to use houdini for lighting and rendering because you don't need to know that much to it to be honest because it's the same sort of stuff you would get in maya but there is a bit of a learning curve as well so i thought i would put that into one video and hopefully it was of use if it was um feel free to you know subscribe and all that and consider signing up to the patreon if you need extra help you can always send an email if you sign up to the patreon there is also content related to the other videos any scene files for some of the videos i create i put for my patreons as well anyway i hope that was of use cheers

Channel: Raycast

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Keywords: tutorial, animation, 3d, vfx, visual, effects, learning, substance, painter, maya, nuke, film, tv, painting, keyframe, raycast, fx, greenscreen, comp, render, arnold, autodesk, mantra, houdini, modeling, modelling, texturing, sculpt, sculpting, rendering, compositing, cgi, commercials, 3danimation, uv, unwrapping, boolean, bevel, gobo, edge, loop, extrude, effect, texture, games, design, graphics, making, after, motion, pftrack, 3de, equalizer, 2015, 2020, free, training, flipped, normals, pluralsight, digital, tutors, gnomon, legacy, camera, c4d, corridor

Id: -se7wsgkE-A

Length: 46min 33sec (2793 seconds)

Published: Thu Feb 25 2021