V Ray Rhino Ambient Occlusion HDRI

hey everybody this is going to be a little bit of an advanced video for vray for rhino where i'm going to cover a few things regarding lighting uh specifically looking at how to manage the sky a bit more specifically use hdr lighting and then i'll briefly cover how to create a ambient occlusion render so the first thing i was going to bring up is the usual v-ray for rhino settings asset editor so one of the questions i had gotten was how to use the sun sky system in rhino but not actually have that sort of blue sky above your image so way to do this is actually just to disable uh i'm under sort of the general settings go down here and disable uh the background so just have this unchecked uh next so gi should already be assigned to be text sky which will look like this and the next thing would be to actually turn on the reflection so if you did this without turning on reflection it would work and you wouldn't have a sky but you'd also anything that's reflecting would just be reflecting the blackness of space without a sky so if we turn on this option here the reflection option and just assign this guy to be tech sky or just sky sorry it used to be called text guy uh just like everything else uh basically when we do our rendering and i've already done a partial one uh where did vfb channel go here it is you can see here the sky is now the sort of grayish charcoal tone and that just means there's nothing there so when you save this as a tiff or png it will be transparent but if you look at the water it's actually reflecting some light again i didn't let this render finish because i was just testing it but that's how you can get that set up alright so the next thing i was going to cover is actually uh how to do an alternative lighting system so in this case i'm going to close out this uh the first thing i want to do is actually i'm going to disable all the lighting in my scene so i'm gonna go to lights which i already already have here and turn off the sun and i'm actually going to do a quick test render just to make sure should be essentially completely black the fact that it's not completely black says there's still some light coming in somewhere so i need to go through and check to make sure that i don't have another light source affecting my scene in some way i'm going to turn this value to 0 because it's going to be using the color otherwise see if that does it okay fully black uh so often times when you're changing lighting scenarios you want to make sure that you don't have any remnants of a previous lighting scenario especially if you're say adding in a new way to illuminate your scene and you have two suns ultimately that can be the worst scenario because it's going to be really bright and it's going to be hard to balance your light so i'm going to do what's called a hdri image as my light source for the scene hdri lights are essentially spherical images that you bring into your scene that illuminate the entire sky so it's basically you take a camera and you take a 360 degree image of an actual sky using a very high quality camera that can take a high bit depth image which just means it has a lot more color information and v-ray on a lot of the other renders can use this as a way to illuminate the scene based on the actual lighting someplace in the world so this website is a great source for this it's called hdri haven if we go here click on hdris it takes a second to load but basically uh this person has put together a whole bunch of these and they've made them free for use so any of these you can download so if you want to have this nighttime sky or this really clear sky just know you are getting a spherical image so sometimes you can use that as a way to sort of render say your model in this field and other times you really is looking for the lighting but if we were to use this forest scene here you're certainly going to get the shadows and context of the forest so sometimes you know you want to aim for these sort of flat scenes that are going to be easiest to get a really clear picture of just what you're looking at which is just the sky so when you download these i'll just click on this one here you also the image below gives you a preview of what that lighting looks like so you can get an idea of how crisp the shadows are for example and this general color tone the real advantage here is that the color tone of the sky is really going to be more unique than the ones that are auto-generated by v-ray using the rhino sun system and they're going to be tightly tied in with the lighting that adds to the scene so the the coloring on the model and your materials and everything else is going to be really matching the sky because the sky is providing that light uh so you can download versions here um i probably would suggest going for the 8k version beyond that i think you get to diminishing returns these are really big file types and might slow things down you might even be able to get away with the 4k version um again just for a smaller file it will go faster be easier on your machine but just essentially download one of these you can also get there's a jpeg one that you can have as a sort of a preview version these hdri files really don't preview well on your screen they have so much color information that it's beyond what any screen can show so they've billions and billions of degrees of color whereas your screen can only show in most cases a million 16.7 million colors is the common color depth of a typical screen so download any of these and again you can look through them there's lots of options here these are all free i've used them and they're pretty great you want to make sure you get a good source for these because the quality of the photography makes a huge difference there are some paid websites as well that can have you know the highest quality you can get and i have a few paid ones myself but mostly this website's a great resource so essentially what you need to do is going to go to dome light and we're just going to place this anywhere in the scene it doesn't matter where you place it doesn't matter really anything about it just go to the dome light it's just going to be this guy here you can also do it through the lighting panel and to add a new light which you would do by going to lights and lights and dome light i'm just going to click it right here in the center doesn't actually matter where you place it and i'm going to navigate to where my lights are it's also good to start saving these i have a whole bunch but i like this one in particular and just hit okay so nothing in your scene will immediately change but if we go to the dome light it looks like i actually added it twice so i'm going to delete the one that i didn't mean to you'll get a preview that looks something like this now the dome light i have only has the sky and below is black so if you're in that case you make sure you make sure you use the shape as hemisphere as opposed to spherical else you will end up with um sort of seeing blackness in the background which isn't necessarily hyper-realistic the next thing you may want to do is so with this image it's going to illuminate your scene uh how it illuminates your scene you have some control over so we could adjust the intensity moving this up or down but what i'm actually mostly concerned about is the ambient light versus the direct light of the sun the easiest way to adjust this is under not that one actually but go down to uh sorry click on uh the texture slot which will bring you to the actual texture that we're using and go to color manipulation uh i'm sorry actually switch it um there's a little color space thing here and i prefer to use gamma it's going to give you a value the first thing is just set it to one i typically find for hdris i actually end up using something like 0.85 on the gamma value and essentially the lower this value is the higher the contrast so the more the sun coming in the sky will affect the scene and the less the sort of ambient light of the sky will affect the scene and it's going to be different for each one of these what the value would be so sometimes you might find that this makes really great shadows but other times you might want a different value i typically go between say 0.65 and .95 depending on the hdri again this is getting a little bit more complicated but not two so now i'm actually just going to do a let's set this to interactive so we can start seeing things because i know because i've changed the sign in my system in my sky i'm definitely going to have to adjust my camera exposure i'm just going to hit ok and give it a second to get rendering so you can see here we have that sky we are seeing sort of blackness in the background that's okay there's a few things we can do about that and this is is indeed a sort of nighttime scene but we're probably going to want to up the exposure some maybe something like that and i'm just going to orbit erase so we can kind of see the whole model and get an idea of what we're looking at here so again you can see here the tone of this image is totally different it's got some blue hues but they're very sort of appropriate and matching to the sun sky that we have here so with this sort of black background there is something we can do in v-ray that's really convenient which is we could turn on the v-ray infinite plane which is just this guy right here click that once it'll be placed in your scene and now when we render again although i hit i didn't hit interactive render so i'm going to do that one more time now when we render you can see basically the earth goes off to the horizon it's just a flat plane it'll take on it's a physical object so it'll take on whatever characteristics of the material or layer you build it on so if you build it on a layer that is all water you could build an infinite ocean if you put it on a layer that is uh you know stone or something it'll be that so you can see here again we're getting some interesting coloring we're getting the reflections of that sky on this water typically this is the way i do renderings i don't use the sunsky system very often because i find hdri just gives so much richer feeling to renders there are some reasons why you might not want to do this though and that is specifically around sort of setting time of day uh with hdris you don't necessarily have as much control i mean you can pick specific ones for specific times a day but it's not like being able to say well what does this my model look like exactly uh on december 21st at noon you don't have exactly that fine grain control so if you're really looking to look at specific times of day these aren't the best option if you're looking for a really nice sort of sky integrated with a model feeling these can work really well okay i'm just going to stop this i'm not going to finish this render the next thing i was going to cover is an ambient occlusion render and this is can be done in multiple ways but in the way i'm just going to do it as a separate pass that you can in photoshop overlay on top of your image so let's see here first thing i need to do is get back to a scene that has no lights turned on so i'm just going to turn off the new light that light is i believe just my dome light here which you can go uncheck it here so again i'm going to do the same test as before and just make sure that it renders completely black okay that's good and now i'm going to go back to my settings to make this work properly i need to add in a different sort of global illumination and i'm going to do this by turning this guy on clicking here and i actually want to get rid of the text sky in this case and scroll down to dirt and just leave that as is that's the only setting you need to adjust there next we need to go to global illumination and i believe we have to click this little guy here to go turn on advanced switches and then there's going to be an ambient occlusion tab that we're just going to turn on next i am going to go all the way down to my material override and enable this and set it to be pure white so you can just click here or just pull this thing all the way to the right side and this should be all we need to do the other thing we actually have to do is this does not work in an interactive we need to make sure that we are running uh in the normal non-interactive mode so both progressive interactive are disabled so now when we hit go all right so that didn't give me exactly what i was looking for that's because i forgot to do one other thing for this we also want to make one other adjustment which is under camera we want to turn off exposure functionally that just sets up auto exposure because it's no longer going to set it to specific exposure values so now if we hit go again we should get an image that looks something like this so it should be primarily white in fact nearly perfectly white on most surfaces and then where surfaces come together you start to get some shadowing and these are essentially ambient inclusion shadows which is the shadows that occur when two surfaces touch each other so we can have some control over this too so if we wanted to have say maybe deeper more intense shadows under our ambi occlusion shadows we can adjust that here we can also adjust the radius and this is in model units so 8 might be a little high i'm just going to do setup to do a region render which is going to be this button and just hit ok again and we see here with that value and the radius set to a lower amount it's really only affecting these areas um directly next to the corners i think that's probably going to be better for what i'm looking for i might turn up the amount and see what that looks like it's probably going to look a bit intense yeah i might be happy with that so essentially once i'm ready just render the whole thing again ambient occlusion renders tend to be pretty quick you don't have to spend too much time on them or simple calculations relatively speaking so what you want to do when this thing is done is save it as a jpeg or png the black sky should disappear and it'll be a transparent image essentially beyond this uh over uh bring this into photoshop on top of your normal stack of things that you've brought in already and then set this to be multiply the layer type to be multiplying essentially it'll add these shadows in on top of other things and it adds just a little bit more definition to your image and can look really nice in my opinion just to give a little bit more crispness in general probably don't leave that at 100 you might want to adjust the percentage in photoshop on how effective that is in fact so in photoshop i have a so this is the image i've used as an example it did come out of thea but the same process applies here and i have a rendering here which i'm just going to turn off multiply and we can see here it's essentially the same image i had to make some adjustments to this one because i didn't do it right the first time i just had to do a sort of levels adjustment to it but that's fine it doesn't really matter you can get an idea of what the impact of this is so if we set this to be multiply and i'm just going to zoom in to some areas where we might start to see this so there's a little shadowing happening here if turn it on and off you can see it just gives you a little bit more definition also in this case so we might find that turn down the opacity of this because maybe 100 is maybe too strong too dramatically shadowy but something i don't know maybe 70 percent looks better and again it's a sort of minor detail but it does help really define edges and surfaces i think a lot better than the otherwise would be okay that's it for this one i'm making another one of these for thea which is exactly the same process well covering the same things essentially just you know done with the instead of v-ray all right thanks

Channel: Michael Rogovin

Views: 9,308

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Id: SPBRKgHSz0E

Length: 17min 12sec (1032 seconds)

Published: Thu Nov 12 2020