Blender 2.9 Caustics | Cycles, Radeon ProRender and Luxcore

hey everybody dj here and today we are going to be looking at caustics and i'm going to be looking at this in three different render engines just so that everybody kind of understands and we're going to be looking at it in lux core cycles and in amd radeon pro render before we begin please go ahead and hit the like and subscribe button that really helps me out so we're going to jump inside blender here and when i first started looking at this and i got a few uh requests to kind of like look at this or some questions and stuff like that i really thought this was going to be relatively easy but i did spend actually um a week or so just kind of researching and testing some things and studying how caustics work within the different render engines and also looking at things in real life so i'm going to open up some images that i took or some some pictures i took when i was out and this is something that you can do so if you take a look at this um these pictures are not the great the greatest or anything like that this is just really quickly i was out at um a store and i was just observing different glass and plastics and stuff like that and how they just kind of naturally existed in the environment and you can see at the bottom here um caustics are it's basically the uh different light paths and how they're sort of like refracted from the glass and that reflected light effects that you see are basically that and i can i can pull up the definition here and this is on wikipedia and you can see here it's pretty long um and it has to do with the light rays that are reflected or refracted by a curved surface or object so uh in our case here it's glass and you know here's what that looks like up close pretty neat effect there and oops let me uh bring this back and you can see like this is a really good effect here there's you know water and how we've all kind of seen that um this is some different you know patterns and it kind of talks about how those rays are refracted by this curved surface here and there's a lot of things that you can do to test this out you know this in the sunlight here's a computer rendering of it and all of that and the thing is that this is you know highly complex and all that but basically my opinion or how i like to uh define this is it's basically the light that's refracted onto a surface from a curved object like glass or something like that and you can see here with the regular ambient light there's really not a whole lot you can kind of see it right here and it is colored because of the glass but it's not really obvious you know there's a couple little effects here but it's not really super clear what's going on and when i let me open this up in a different viewer here so that's easier for me to take a look so let's open with earphone view if you don't have ear front view i highly recommend it it's free so if we kind of cycle through here you can see i got closer and you can start to see it's focused here but you can see there's some rings right here and here you can see that when you shine a light through it and my wife is helping me here by putting her phone with the led right next to it you can see it shows those uh rings a lot clearer and that's with the light right up against the glass i didn't get that in the shot here but uh basically the led light is right next to the glass and that's what's showing this effect here and there's another picture of it and there's another one there so you can kind of see how the lighting where it's placed and the brightness of it actually changes how the caustics are working with this particular glass and i took a close-up photo so you can see that on the surface there's these very very fine sort of like um imperfections that help to push that sort of refracted glass effect and here's another object you can see here the caustics are very very you know slight you can see it here and some of it see-through right here and it has to do with you know the thickness of the glass what kind of glass it is if there's any sort of volume like here there's a volume absorption of a green effect here and the ambient light you can't really tell but once a light is shown is shined through it really really close you can see that it has a completely different effect okay so that's basically what caustics are and how they are in real life okay so the question is how do you replicate this in real life now a lot has to do with the thickness of the glass you're making or the object that you're using uh it has to do with the actual geometry if it's just a flat object or just a very very smooth object you might not see these sort of effects so the actual geometry is going to affect it so how do we replicate that inside of cycles or lux core or prorender and this is uh i thought it was going to take me not very long to do this sort of thing but actually took me a lot longer than i thought and if we just take a look here let me just save this really quick i approach this in a couple different ways so here is here's the scene and let me turn these on here so i have a light that's shining through here and i have a light that's right up close to it kind of like um the led light of the phone so it's really really close to it and i could get closer but i kept it this distance and um then i have over here if we look here we have uh an hdri that's at a strength of 0.2 just to give some ambient light to the scene okay now before you can actually make uh the caustics visible you need to make sure that you go down to uh light paths caustics and uh bump this up here and the filter glossy here says adaptively blur glossy shaders after blurry bounces and stuff like that to reduce noise at the cost of accuracy so um this can actually change how those caustics are calculated let's just leave that as it is for the moment and let's take a look at this uh oh really quick for this this version all i'm using is a normal map from the amd radeon prorender material library it's a rubber normal so it's this uh lined let me see if i can zoom in on this large so it's basically vertical lines here that i made kind of similar where it just like rounds around the glass and i use that as a normal map and i pipe that into the glass and then i also added a volume absorption just to see how the coloring effect is done and if we take a look at this and i'll throw this into the rendered view here let's take a look and see how this is rendering so here it is and this is what it looks like at the moment and if i go in here let's do because we just want to really just look at a particular section we're going to crop to this spot right down in here okay let's zoom in and you can see as it's rendering out you can start to see that effect right there on the the bottom here and you can see even though it's a kind of not so great render you can still see that there's um a caustic effect happening okay so let's uh test this out and see what happens when we take the filter glossy down to a zero which basically means don't filter out any glossiness and it basically starts to create more of the um it's actually not zero let's go to ten yes let's go to like 20 or something like that 20. oh looks like 10 is the most and you can see that like the more you pop that up the more this should be sort of um seen here so if i go 0.1 you can see that you um get kind of less of that effect there at least as far as how quickly the samples are calculated and then if you pop this up to a 10 you get more of the caustics effect okay so that is one way of uh doing this uh this method here so this is just a very simple and i have this as a multi-scatter but you can you can use any of these other ones here for the type of shading and then a volume absorption to get that color and then you can get a caustics effect just like that so i'm going to put up a final render right here of what this might look like if you finish it up and you know we're we're happy with it so this is what this version looks like and then what we're going to do here is we're going to uh or i'm going to show you how you can do this with a more complex shader so uh you if you looked online you will have noticed that there is a gentleman this individual right here gleb alexandrov who knows a lot more about glass shading than i do and at this particular website the creative shrimp website you can actually download the file and the node setup so you don't have to recreate it yourself but if you want to understand which i recommend you know going through this if you want to understand how it works and all that and how to adjust it you can do the entire tutorial here and i'll i'll provide the link in the description below um but basically i took his and i hid some sections changed a couple things and adjusted how the normal mapping and bumps and the volume and all that kind of stuff to be more of what i want and this is what ended up happening with that so you'll see right away there's quite a bit of a different effect happening with the render you can see that there's a lot more going on as far as what's visible you can actually see some of the ring shapes over here from the uh normal or bump map that's on the object and in general you get a lot more of you know a more fun effect of these caustics and what is really going on here if i can open this up really quick and i don't want to lose anybody um but right here let me see here so basically what's happening is they're taking or what's happening here is that you're taking the light path okay and you're basically changing how the light path into the shadow is being rendered okay and there's a couple different ways that this is shown let me see if i can so that's the dispersion effect that i'm not using which is fine but basically let me get back over to the uh ray length so right here the uh absorption ray length here it it's basically saying take the shadow and change it up so that it's more um affected by the actual uh glass material in this way so you know long story short you know what i mean because there's a lot more going on here and there's a couple different ways to do it by using uh there's another one where you can use a dot product and a couple other things like that to create this same sort of effect and you can look online and find a few different ways of doing the same thing but basically they're altering how the the shadow or the ray length um or how the shadow is being uh projected onto the surfaces here okay and this is another area right here where it says fake caustics that's the area that actually creates the um more of this effect so you can see right down here it's using the normal and then the geometry here to create this dot product and does a couple multiplies and stuff like that and basically what this does is it uses your object information and a couple other things to create a more faked sort of like caustics effect and this is really the the way even though this is like a lot more complicated than some others um ways of doing this uh this is really the general way that this is done inside of cycles so uh it's not really um as easy in cycles to create this super caustics looking effect here or the uh fake caustics looking effect you can see it even shines back onto the other sides over here um but this is how it's done uh if you want to boost your caustics and again i'm providing the links below on on where you can find some of this information now the other thing that uh is affecting this and i'm gonna show you it in here because it will uh update a lot faster than some of the other engines and other ways of doing this i'm going to just show this section here and i'm going to show you how the lighting is really affecting this so if i take this little guy right here and if we look at the caustics here and if i start to scale this up you'll see that the caustics are a lot more soft okay and then if i scale this down like really really really tiny the more that's really ugly but it's basically like a super super super tiny little light that's super bright and it's causing this effect to happen so if you wanted your caustics to be a lot sharper than what's currently happening or what you're currently seeing you need to scale your lights to reflect that or uh i don't know if that's like a pun or something but basically the the size of your lights are going to change how sharp the definition of the caustics are between the different lighting effects so uh there's that one right there that i used a little area light and then for this spot lamp that i put up here let me increase this size here you can see here the radius is a 0.01 if i set this at a let's say a 0.5 or something like that it's going to change the sharpness of all of these other caustics that are being created from this lamp right here and let me turn off let me just save this really quick and i'm going to turn off this other one and let's see what those caustics look like just with this spot lamp here so you can see it a little bit easier and there you can see that those are the caustics being created just by this light here and the ambient light and if i take this down to a 0.01 like or yeah 0.01 you can see how sharp that ends up being okay so again the geometry of your object the thickness of your object as far as the glass shading and the size of your lights how bright they are and the way that your node setup is and i'm sorry this is so you know crazy but this is you know it's a really great um uh shader and i strongly recommend downloading it and keeping it but that's basically how people are doing this uh faked caustics look okay so uh here's a render of how this looks when i finished it and let's move on to the next thing so i'm going to show you i'm going to keep lux core for last i'm going to use prorender uh next so that you guys who are my pro render fans can take a look at that so i'm going to switch this over to radeon pro render and turn on the pro render section now i'm using 2.0 because uh 2.0 actually works better for caustics than uh 1.0 and uh this is just something i discovered 2.0 is just better at it the only problem is that volume absorption doesn't work so uh unfortunately you're not going to be able to see the cool colorful look but i'm going to show you how this looks inside of prorender and this was actually the hardest one to get working so i basically tried or attempted to keep the same type of lighting i had to change it quite a bit to get it to work or at least get it more obvious for this render engine than the other ones so um if it's a little bit off or a little bit different you know sorry about that but that's just what it is so you can see down here the way that it's rendering it there's a lot of fireflies okay and or you know this these little points of light which are generally called fireflies and i have the viewport at a 50 right here let's change that to 75 and we will reset that so it's a little bit clearer and what you'll want to do is you'll want to make sure that your samples you want to set these kind of high and you'll need to set your quality i set it at max okay and then down here where it says clamping i set the clamp radiance to 37 because that was similar to what the lux core clamp radiance ended up being so i wanted to try and get something a little bit similar to that and you can see right here and it's a little bit hard to tell with this you know previewer but you can see right there that's where the caustics are right here and in this section right over here okay and i'm gonna go a little bit closer and just remember that this is still in beta um and i have a uh a review of the more recent i'm actually using the uh the newest build that was available for weekly but i do have a review um of one of the weekly builds and i'll put a card in right here so you can check that out if you'd like but you can see right there that's where the caustics are and they're not as cool as they were in cycles um with that other shader and if we take a look at the shader that's being used here it's very simple i have the uh the normal map here and then here is the glass and you need to make sure that you check on this allow caustics right here otherwise if you don't if i take that off you can see that it doesn't actually do anything as far as the refractive shadows and anything like that so clicking that on does change very much how everything is rendered as far as glass is concerned and it also says that in order for the caustics to work properly that you need to make sure that there's at least a little bit of roughness on it i found that that doesn't really matter and that the caustics kind of show up regardless if there's any roughness on there but i don't know and you can see right here refraction absorption distance it's set at a two um so we should actually see an absorption here but the current 2.0 does not allow for volumetrics at the moment so that's why you're not seeing any uh colorful glass or whatever but you still do get a pretty nice little render and here's what it looks like um i set my uh samples to like 1500 i think for this um and it's at a 4k and then it's you know for youtube it's down sampled to 1080p but um that's basically what i did there i just set the samples to max so like 50 and then uh the samples to 1500 and the uh in the area where you can do your clamping i set it to a 37 and i got something similar to this so if you need to or want to use prorender this is currently the best way to do it and looking back into uh blender right here there is no way to get light paths right now so if i go in here and i go to um let's see rpr lookup which has some interesting stuff like uv maps and stuff like that there isn't a light path here and if it is one of these i'm not aware that it actually does what it's supposed to okay so there's no way to actually if you get like um you know geometry or something like that there's no way to actually get that light path information for your shadows and to make a custom uh boosted uh caustics effect you just can't do it in here yet so hopefully they figure that out soon or they add some way of you being able to boost the caustics in the uber node for glass i don't know that's just not something that i think they're worried about at the moment um and this is also in beta so it could change a lot between now and when it's actually fully released so let's jump into another engine and this is the one that i'd say if you don't care about render passes and you don't care about um having to have it in cycles this is what you want to do um you want to use lux core and before you actually uh can see the effects and i will turn it off just so you can see uh let's see where is it here light paths light tracing okay so um if we take a look at this here and this is not a there's not a crash course on this engine or anything like that i'm just explaining how this works in different programs or a different um engines so if we take a look at how this looks uh currently in this render um you can see it's kind of bland there's not really a whole lot going on uh it's what you would see in any of the other ones you can see that it's filling in right here with the caustic effect if we zoom in a little bit you can see that there is not really a whole lot happening there's a little bit of the caustics being rendered here but not really a whole lot well the easy thing to do in this engine and again this is specifically to lux core is that they have this setting right here that's called add light tracing and before i do that i'm just going to click on the object and i'm going to show you what the materials looks like and in here you actually have to use this i mean you don't have to but it's better if you do it the lux core material nodes because they have a different way of doing things and in here you can see that there's a glass material this is the settings that i have i don't have a dispersion on it like i can show you what that looks like in a second but you can see that it's pretty simple i have a volume that's put in there and then down here i have the bump map or the normal map that i'm using to create a bumpy surface here with these rings okay so if i take this i'm just going to show you what this does right here this dispersion if i take this and i put the put this to a point zero one you can see that it starts to add a a dispersion effect which basically separates the red green and blue channels into different colors okay so it basically creates this dispersion effect down here that you would see like in crystal or something like that you can see it kind of here i'll zoom in a little bit more so you can kind of see what it looks like and there you have those effects being rendered hopefully this is visible on youtube but if you download this and i'll put the link to the the in the description to where you can download this engine um you can play with this and see everything that it does so the main thing here that i want to show you is how with this click of a button you know in quote you can basically add a whole different effect to the caustics so if i turn this on we should be able to see a very different effect here and let's actually reset the engine let's go here and then go back to here and we should see a very different effect so there you go you can see that there are completely different sets of of uh refracted light or these caustics that we'd seen on any of the other engines so far and this is actually far more accurate than the other ones because the other ones are kind of faking it to you know make it look more like what it should look like this for some reason or you know this is just how they created this engine you can really see those refracted uh light rays off of the object and i'm just going to turn off dispersion here because i don't think it's really important to what i'm trying to show you you can see right there there's the coloring effect from the volume that's from within here and you can very clearly see the rings right here from the object or from the uh the bumpy surface so i'm going to go ahead and turn off the clipped area here just so you can see how some of this looks on the other parts of the background and everything so if i take a look at this in the rendered view again we can take a look at that and you can see that that effect is very clear and obvious right through here and throughout the scene we get that really neat caustics effect and the same rules apply here as far as the size of your lighting and how clear this stuff shows up so if i take this lamp and i go and i change the size of it here to a .5 you can see that it's not so obvious you see that it's not as obvious those rings okay it's more diffused and that's because the lamp is much larger so it makes sense that it wouldn't be as sharp in those uh of the obvious caustics that are being uh cast there you may have seen this right here this little laser thing i'm not going to use it um it basically creates a laser beam effect where it shoots a ray of light straight forward whatever the direction is and it will make some really cool effects i'm not going to show that in here because i think most people aren't really going to use this sort of thing and i might show this in some other um tutorial later but basically if you're if you want to have realistic glass effects with all these caustics and stuff you can use those other methods that i showed you earlier but really lux core is the engine that's going to give you what you need and the great thing is that it's free so you can download it and use it as much as you want and get really great effects uh there are some limitations there aren't as many uh render passes as some people want and there are some you know reasons why you may not want to use it you can check out my render engine comparisons videos to check it out especially when it comes to volume metrics it tends to be extremely slow when it comes to some volumetric renderings but hopefully this gives you an idea about what kind of engine you want to use for your scene when you're creating something that actually has caustics and stuff like that so that's going to be it and hopefully it helps to explain to you how you can actually get these really neat effects in in your glass as far as caustics and stuff like that i'm gonna show uh right now a couple of the different uh render passes that i did with the different engines and this isn't a one-to-one comparison video or anything like that so i'm not gonna provide any you know times and you know um all of the details as i normally would but this sort of gives you an idea about what you can expect to see when you use these different render engines and how you can um change up your node structure in cycles and what you can expect when you're trying to create glass in prorender and how to be frank awesome lux core is at rendering out caustics and making your scene look amazing if uh glass encaustics is what you really want to see so thanks a lot for watching let me know in the comments below if you found this helpful and if there are any sort of uh tutorials you'd like to see me do and i'll see you next time on dj tutorials

Channel: djtutorials

Views: 14,950

Keywords: blender, radeon prorender, prorender, blender prorender, blender render engines, prorender rendering, raytracing, blender alternative render engines, glass shading, rendering glass, how to render glass, caustics, how to turn on caustics, advanced shading, volumetric glass, luxcore, luxcore renderer, cycles glass, boost caustics, prorender caustics, luxcore render, caustic issues, enhance caustics, render caustics, fake caustics, glass caustics, better caustics, better glass

Id: fxVwr4q0qvM

Length: 28min 56sec (1736 seconds)

Published: Wed Sep 23 2020