Maya Tutorial: Lighting for VFX Part 1 - HDRI Setup & Balance

[Applause] [Music] so okay so we're going to look at how to set up lights for a vfx shot this is what we're working with at the moment so here is our sequence so i'm just going to play a bit of it so the thing we need to keep in mind first is what is going on with the lighting so i can see we've got a lot of green screen here which is fine but we're going to cg this room so we've got a scene with all our assets in there so far um this room on the left-hand side we see these actresses walking through it and they look pretty dark to me you know ignore the fact the green screen is bright the green screen is bright just so we can clear out so these people are dark so the the room we have on the left hand side we need to make sure it has um walls to create shadows for that area this background area we need to keep in mind that there is some light spill coming across there so whatever is behind there in terms of the effects will there will be some light coming through from you know it could be an environment in the background it could be a you know a landscape but we would just have to you know monitor this this lighting and just keep it consistent uh the same goes for the far right hand side you know all this stuff here we're swapping out in cg so all this area we need to look at what's happening with the lighting so in fact if i add a color correct node to this if i bump up the contrast then i can actually see a bit clearer what is going on with the lighting so as an extreme example adding this contrast to it i can see that this actress here is being hit by a spotlight so i would assume that it's going to be the same one hitting this baby so in the scene in this we do have an hdr but we're just trying to look at the other lights so there's probably a spotlight hitting down there and it looks like there's another spotlight hitting this top roof bit there's quite possibly another one hitting this side because here it looks like it's vignetting to hit you know these people we can see there's a strong fade off when the spotlight is hitting this actress so we can make the assumption that we should probably add a light in in cg going there and then probably one up here and maybe one here as well the actor in the background looks pretty dark so it might just be a case of keeping ambient lighting there as well so off the bat i would say you know we'd have the hdr so that's light one light two probably spotlight light three the next spotlight light four maybe another spotlight or soft box to hit this area light five we could have a light a slight light it depends what the background is you know if this if the environment behind here on this left hand side is one area then we would probably want to have a soft area light or soft box something like that that's just what i'm thinking at the moment but we can we can see what it looks like in the end but this is just the the raw plate we're looking at now okay so before i continue i will say um in this example i do have an hdr so for anyone that doesn't have an hdr and is lighting vfx i would say you just want to find an hdr that looks in keeping with the general lighting of your shot and even if it's not that great then you can just keep it at a lower exposure there's a website which i can just show you now called hdri haven there are a few others but you can get some hdrs here and if you do take a lot from this website i would say donate to them you know it's really useful but they have a whole bunch so outdoors so if i didn't have an hdr for this particular plate i'd probably just look at it and then scroll through the menus here and then pick one that was fairly in keeping okay so what i'm going to do for anyone that doesn't have an hdr and they're watching this video i would say go to the time stamps and skip ahead because i'm going to take a look at my hdr so i've actually put it in maya already so this is what the hdr from set looks like straight off the bat i've increased the exposure to about nine and we do have some reference below so these are just cropped images of the chrome ball from set and then the gray ball and the macbeth chart and fortunately enough these were um so these reference images are screenshots essentially from the filming camera so the camera that was used to take the hdls that was just some canon and then we um so the project was shot on an alexa so the these are actually what the plate was shot with so we need our chrome ball and our gray ball to look as close to these as possible so you can actually see that we have the reflections in our chrome ball already are similar to to our reference so in a in your scene i would say whatever project you're working on i would say if you've got all these all this other geo in there you might want to put it on a separate layer so i've put all my geometry on a separate layer and i've so i selected it and then i clicked display layer add sorry create layer with selected objects then i double clicked on here to rename it to all scene geo and then i pressed the v to turn it off and if you've got any lighting in there at the moment i would say delete it i then created a skydome so to do that go to arnold likes skydome then in the sky dome on the right hand side i added in my hdr in the color slot so you go to color you pick the hdr so here is mine in there if it is a true hdr image your color space should be raw so this exr format but it is a 32-bit um image that was actually converted the original image um i was i think i re-exported it from an hdr format i then upped the exposure because with an exposure of zero so my default exposure of this looks very dark from what i remember so this is the hdr straight from set combined and then if you if you do have reference from your onset camera then in this example i just made a polygon plane put it in front of my set and then went to right click and added assign favorite material i added a surface shader this is just a flat shader see you could do that and in the shader i renamed it remember to rename everything so i called it onset ref shader in the out color i put in my image so this was just this image is just me getting the footage that was shot of someone holding these uh balls and then the macbeth chart on set print screening and just photoshopping together so i've put that image in there and what you could also do is in the shape of this plane i should rename it so i'll call this onset ref geo something like that in the shape tab in the attribute editor you can go to the arnold tab and we could turn all these off because we don't want our spheres to be influenced by this this is purely there just for our own reference so i'm going to turn all of these off apart from primary visibility we need to be able to see it once you've done that create two spheres put them somewhere in front of your scene so i'm actually viewing through my render camera so this render camera has already been tracked and it's at the first frame of this sequence so my render cam is viewing here and i've put um put these shader spheres pretty much in front of it so you create your two spheres um the first one the grey ball i'm just going to leave it with the standard lambert which gets applied to everything and then the one on the left um i'm going to i applied a arnold standard surface shader so you want to go to assign new material go to the arnold tab and find a material called ai standard surface then in your presets uh there's loads of different presets that solid angle have given us so there's a chrome one so you can scroll down to there and hit replace and this pretty much just whacks up the metalness to one i think it might change the index of refraction possibly but um but yeah so after you do that so you will have your hdr and then you have your two shader spheres in my instance because the hdr is so dark i see pretty much nothing apart from my reference plane the alpha's pure white when i press the alpha button because we do have our hdr image visible it's because it might be useful in the next few moments so i'm going to start by putting up my exposure to 9 which i think is what i had before i'm going to minimize my render tab just so i can play with the settings okay so now the process would be i mean i'm not saying this right or wrong but the process i would take to get nearer to this was i would start by trying to adjust the exposure of my hdr to get to a similar level to to this image here if i want to because the the lighting um because i know where this reference was actually taken on set i could in fact move these balls to be closer to that location so or i could just duplicate them so what i mean is in my perspective you can see the shader balls are here and then i've got my reference here this hdr was actually taken approximately there so this is some of this geo is just a rebuild of the set so it's pretty much in the right sort of place i couldn't actually remember where i placed these balls but it looks looks okay so in that that case what i can do is i should probably rotate my shader sphere so i'm going to press play to render and i can slowly rotate my shader sorry my hdr around i could do it in the perspective or i can change the rotate y-axis because we just want it to turn around in a 360 fashion so as i alter this you will see the rotation i just want the rota um i want the because i know that this shader this chrome sphere is in the right place in set in relation to here i'm just going to rotate it to be as near to the reflection that we've got in the reference so we're getting there so i'm changing the rotate y to about i think that's about right and all i'm looking at is just the reflection because we have the hdr and we've got the reference you know the facts that i know are this was these screen shots here they are from my camera so they are we're trying to light cg in the same way that these are being lit because this is on set so knowing that just to reiterate i've placed a chrome ball and a lambo in that same sort of location in order to match uh match the lighting so using the chrome ball with the hdr we can now rotate this hdr to match here and that looks pretty much okay to me i might just reduce it by five in the rotation but as you can see the reflection is pretty much in the right place i'm just going to try 65 quickly okay so yeah that looks that looks pretty good to me so then the next thing to change would be i'll go into the exposure tab i might just say the screen um screen capture thing so just so we can look where we've come come from as well so the exposure in my render looks a bit too bright so i'll change it to six um that looks better but what you can see in our hdr is the white points are looking it's uh in our in our plate it was a lot more orangey rather than our hdr so what we could do is we could just use this as the base for our lighting and then we could add in lights with a bit more color but i think it would be beneficial to actually grade our hdr to be a bit more like like this so there are two ways we could do that what we could do is we could load in photoshop our hdr so this is the hdr and i'm just going to put up the exposure purely so i can see what's going on so you can actually visually see where it was taken whoops so the person was standing in between the baby and this doorway and when we look at the plate we can see so they were standing about here in front of the baby and this door so that's really useful and brightening the hdl we can actually see the lighting so when i talked at the beginning of the video about predicting what lights would be used i can actually see if i just add some levels uh tweak this bit add a bit more contrast it's a bit weird looking at it because it's flattened out hdr i could see there's lights here there's one spotlight there's another one then they actually have this big um white sheet which is kind of acting like a diffuse soft box almost but this is just adding diffuse um diffuse lights or lifting the shadows so we can count that so if we count the lights so we've got hdr so that's one spotlight one so that's two lights another spotlight three then we have this sort of um softbox type things that's four there's another light another mini spotlight in the green screen area so that's five and i think that's it so that's five lights so i'll just double check that so hdr mini spotlight here it's two spotlight again three spotlight again four and then this softbox thing so using that as reference in this i know not everyone watching this will have an hdr but because we are lighting to the plate and we have the hdl we must use it so we can build our scene up from that once we grade the hdr a bit then we can add in these other lights as our base point really okay so let's go back into maya and we've changed the exposure so it would be good to change um the hdr a bit to give us these sort of soft orange bounces because an hdr is expensive to render because it's giving off a lot of global sort of lighting so there's two things we can do we could grade this in photoshop on nuke so if i was going to do that in photoshop i'll quickly run over so what i would probably do is i would get my onset reference and we have the macbeth chart or we could use this as a reference i could color pick from the whitest point so like one of these if i wanted the actual whitest points or i could color pick from the white point here because in my render the white points were looking very bright if i just quickly jump in maya where is the render so they're very harsh so we just want to pull back those white points because there's a lot of like orangey spill going on in the in the actual plate so let's jump back into photoshop so if i was doing this in photoshop as a quick example i go to my onset reference if you have any and pick the whitest point click ok so i've changed my foreground color in the palette to this brownie color then i'll jump back to the hdr which is very dark so i'm just gonna turn on this exposure which is justice here i just want to be able to see okay and then i'll create another adjustment layer in the bottom right hand corner create a solid color and by default it looks to my foreground color which is this brownie looking thing so i'm happy with that i click ok and then i just want to blend blend it over so let's try multiply so now it's affecting the it's actually going to affect all the colors and it's adding a bit more of that warm browny orange look you can see what's happening on the lights so i'm mainly focused on the these spotlights but you can see it's actually softening um the look and it's giving us more of that tinge so if i'm happy with that then i could turn off my exposure and go file save as do in excel so that's one way of doing it something else to quickly keep in mind is the green screen thing we can i would recommend keying out you could photoshop this um like just paint paint over it i'm gonna use nuke to remove and quickly key out the green screen because this green is gonna spill onto everything else okay so as i've done this in photoshop this bit of grade i'm just going to save this out so i can save it um because my original image was a exr this is a high dynamic range image i'm just gonna keep it as a [Music] exr cool so that's saved out so what i'll just do is now back in maya i'm gonna save a screenshot and i'm gonna load in my hdr so just go into your dome light and load what you just saved if you've done this in photoshop you could do the same process in nuke or i would just say we can just do this all in maya so i'll show you the maya method as well but i'm doing in photoshop initially because pretty much everyone has photoshop okay that's interesting so because we have multiplied a color over we will get a darker result so that's before so pre-grading post grading but you can see we're getting these more orangey brownie values it does look pretty nice so in my hdr so select your your dome your skydome i'm going to leave it rendering so when you press play it will just keep on rendering by default so i'm gonna change my exposure it was six before and now i just need to bring it up a little bit to be more in keeping so i think nine's slightly too bright and eight in the exposure was slightly too dark or maybe maybe eight still looks quite browny in in the hdr from set so that's when the next adjustment would come in so there's before and there's after before and after so because i've left the visibility of the hdr in the background you can actually see the result of the grade so if you look at the bricks like um so this is the before image if you look at the bricks here from the hdr and then you compare them to what you can see of the bricks in these shots you could see they're a lot whiter and flattened out whereas after the grade we're warming up and becoming more in keeping with the color tones like these small sample of brick you can see let's save another screenshot a snapshot whatever this is called great so i'm going to stop the render for the moment and what i can see is we have softened the lights off a bit i believe um this looks quite blurred out but i think this is purely because the chrome ball there's a lot of like smudging and grime on it so we can't help that um we want to change the color of the of the um we want to grade it a bit more basically so we can either jump back in photoshop and continue that we could probably layer up we can use our color palette and you could re-grade over or if we're happy with this as a base result then we could color correct our hdr in maya so i'm going to do it that way but depends if you are lighting for a sequence like in a vfx film or something then you would probably want to grade the hdr for that sequence okay so i'll select with it hype shade open i will select my skydome and display in and output connections which is this button so now we can see we have this is our file we loaded and then the sky dome so within here what we want to do is in between this connection there are a few utility nodes that we can use so on the left hand side in the arnold tab you have all these utility nodes which have different uses but all i want to do is color correct so i can actually just hit tab and type ai color correct and now i can intercept this connection so i can draw a line out from my hdr to the input of this color correct and then out back there okay maya's just thinking about that the image will still look the same all we've done is just added this in between into the connection but we have not changed anything so just to confirm that i will render now save a snapshot so yeah nothing nothing has changed there's my before render there's the after so that's good okay now with the ai color correct there um you just want to make sure you've selected it so that as you're rendering that's harder for me because i'm recording this so i have to do everything on one screen so i just want to be able to manipulate the values on the side whilst rendering so i'm going to hit play and let it begin to render i don't actually need to render the entire image so i'm just going to crop what i want to see okay so it should just update that section now and what i could do is start to play with the hue hue shift if we want to bring it nearer to a brown or yellow so i'll just raise this slightly just bit by bit just to see what um what number might take us nearer to what we need or you could just drag this around a bit um i'm not exactly sure where the brown values would be because we don't have a visual display of the hue so might in this instance for me it's just a case of just shifting this nearer to wherever the yellow brown values are the moment it's just completely destroying the hue okay so going up from one is changing it to be a bit more blue so reducing the number what's that doing so that's taking it mult purple is another way we could do this if in the sky dome what you can do is change the um there's a color balance section if you want to see a visual version of the hue scale then you could always go there however using a color correct node is a bit more useful because if you're ever sharing a scene with anyone else and they can actually see what you've done okay let's see before and after okay at the moment i'm not liking that so i'm just gonna i'm gonna leave this on zero and i'm going to change the exposure actually not yeah i'm gonna reduce this slightly okay i'm gonna play with the saturation just to see what what happens like maybe add a bit more because we we degrade it so we got the white point and we added to that so it does seem like we might need a bit more saturation okay that's better it's a bit better like before and then after then we'll probably have to brighten it up again i'm just looking at the colors that we're seeing in the reflection here so now we're pretty close and i would say i'm quite happy with that um i think there would need to be a bit of slight hue shift but it's a case of just playing around with it because we can see our grey ball is slightly off but this is pretty close i mean let's look at where we started yeah so this was the very start so the rotation was wrong and everything so that's before and after uh maybe i should do a before and after at this point because we rotated it into the right angle and we decided that the white points were very bright and you know everything we needed to get more consistent with what it was actually filmed on so this was taken with the canon um dslr and this is from our plate that was shot in an alexa so i think the last tweak would be to raise the exposure back up so i'm going to take a snapshot of this render and then in the left-hand side select my sky dome and increase the exposure so we do need a brighter but but then i still think there needs to be a little bit more of color correction but we're pretty we're pretty near i mean again before and then after like i'm looking at the shadowing i probably should have turned cast shadows off from this chrome because we're getting the shadows on there which bit distracting um you could do that in the shape area of the sphere whereas it car shadows there you go problem solved um but yeah that's pretty close so i think for setting up an hdr from set i'm going to say i'm going to leave it there and then in the next part we'll continue looking at this shot and adding lights for our vfx shot

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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: DIt7l5uUlKU

Length: 34min 59sec (2099 seconds)

Published: Thu May 21 2020