Rendering Paint Effects with Arnold in Maya 2018

so in the short series of videos we're going to look at paint effects in Maya 2018 and using them in a couple of ways two things are important to think about one is how we can use paint effects with mash for example so the grass here in this area and also how we can use paint effects and render with Arnold it's nothing really fancy but they're just a couple of things that have to be considered in order for it to actually work and we had to remake shader and maybe change the geometry a little bit just so it renders a little bit better so why don't we just start with the idea of what paint effects is because we're gonna have to get into that for both of these things we also talked about making this sort of water shader here there's nothing really fancy and it kind of looks crummy but it's got an interesting way to use Arnold's transmission in the AI standard surface shader okay save this and open a new scene so if you want to use the paint effects in Maya you can access the different brushes or the different shapes that you can make through the generate menu which is under modeling so you can go to get brush and you'll see that this opens the commonly available content browser which can also be accessed through windows general editors content browser so we can get to it there too but there is a section for paint effects here and you can see you can create a wide variety of things with paint effects the thing to be aware of with paint effects is this is pretty old Maya technology it's been in there for a long time I haven't been that many changes to it other than a few updates a few years ago with occupational area so it can sort of stick to objects or fill objects which is kind of interesting but we're gonna look at just some basic uses and you'll see some of the limitations of the geometry it's not very high quality and textures are kind of crummy and you know all that kind of stuff but we can change some of these things so let's start with something simple what was that one that I was just showing you I think it was birch it was a birch tree so I take this birch and then I just so you can see I've got a brush now if I just click and drag and then release it will grow one tree if I kept painting you would oh this one set just to grow one I guess some of the brushes if we go into grasses grasses for example and we'll do this in a bit if we grab grass clump if I hold them be left my strike and make my brush bigger but you see as I brush it will make more and more so let me close this so when you create a paint effects object it creates a transform node just like everything else so you can move it around also creates a stroke node so when I was painting so if I just launch this again the paint I'm painting along a stroke you can see there's a curve well maybe you can't there is a curve down here at the bottom and it paints along the stroke and some of the settings for paint effect can be paint effects can be found in that stroke such as the display quality a few basic things here there are some interesting things you can clip the stroke so you can actually make it shorter or bigger we're not seeing it here if we grabbed a different brush there's some linear brushes some brushes that are drawn along the stroke and some that have grown out of the stroke so let's say here so intestines we paint these see this is one that is grown along the stroke the tree is what's called a tube that grows out of the stroke so the intestine here I can animate something like the max and min clip and you can actually animate the curve there are lots of other things you can also do here but let's not worry too much about this right now I'm more interested in looking not at the stroke but at the brush so the birch spring light one so this is called the brush and this is a mesh fresh so it's actually making a piece of geometry and I don't want to get too lost in here but there are things like the global scale which is useful just for turning up everything making everything bigger or smaller uniformly brush with if there's the when we saw the grass the brush width means how far around the stroke it will draw there are lots of other things in here let's just jump down to tubes so creation tubes per step so this has got a very low tubes per step that's why even when I did a long stroke we only got one tree you can randomize this segments is how refined there will be so you can see as I turn this up its subdividing this even more it changes the way the branches will grow up things like that length min length max so this is sampling among a bunch of them all on the same stroke this will be the variation in their length also it's same with their width whenever you see a 1 in to 1 means at the base 2 means that the tip can randomize that and so on you can draw a width scale as well so if you wanted to have a certain profile shape so the tube direction is most of the time going to grow along than normal so out from the curve that you drew then there's elevation and azimuth so this controls how much it's leaning over so you can so this is sort of spinning about its axis I think it'll really know that elevation you can make it lay down anyway growth so the whole analogy that's used for paint effects is plants so even if you're doing a teapot if I go into Windows general editor content browser and choose under and gets fun mesh probably like a furry teapot I draw this that is also using the same analogy of branches twigs leaves flowers and buds but they're using it probably this is a bud this is a bud the handle is probably a branch or something or the leaf I don't know anyway just so you know it's all built on the same analogy it's more obvious clearly when you're actually making a tree so if we go into the brush if I turn off leaves no more leaves turn off the twigs no more twigs turn off branches see this one looks like most of the leaves are growing off twigs so these are just subdivisions along and you've got settings for each one start branches how often they split so it's a procedurally generated tree structure it's not constructed beautifully or anything like the branches don't actually connect to the the trunk and things like that they intersect with it and they move with it but there's no nice connection between them and if you got it really close you know you would see that it's just these planes or shapes that are stuck into each other leaves are usually just planes with an image of a leaf and an alpha cut out on them and so on so you can go through and look at all these things one interesting thing that you can do with these which can be kind of handy it's under this behavior menu you can turn on turbulence and so this one by default has tree wind turned on so it doesn't always play ok miraculously today it's playing so you can see it's trying to make it seem like it's tree wind so the trunk isn't really moving but the branches and leaves are there are different types of turbulence there's grass wind you have a grass type paint effects and then other types of things here so this is kind of Handy actually and under generate here there are some animation tools so brush animation you can force it to loop so if you want something that you can just render it once and repeat over and over again there are also things like brush Springs which will force the brush to react to four transform forces so if you animated moving then stop it suddenly it can animate as if it's responding to that force anyway there are lots of things you could do but let's look at what it takes to render this with Arnold so if I put let me just save my scene here not there so pfx demo okay so if we put in an Arnold we'll just put in a sky dome light click render we'll get nothing that's because Arnold can't render paint effects so why are we talking about this right it can rain to render paint effects have you converted to a polygon so we just want to select the brush go to modify convert paint effects to polygons okay so give this problem but even though this is a polygon now it inherits that animation which is also handy and if we go to render now renders not nicely in any way but it will render it will cast shadows so the problem is the shaders that it uses and the way it deals with textures we've got to fix that so it's not a big deal this isn't a great tree to use because this the tree is actually just a flat plane I'm actually you inflate this tree and grab a different one so I'll grab an oak tree cuz I know they've got some volume nothing too heavy oak medium let's try that okay that's pretty good so now you can see this one actually has some shape we still have to convert it to polygons if you have lots of these these can make your scene pretty heavy again if we render this it'll not be good one thing is the specularity is turned way up and it's going to be super shiny but we're just going to rebuild the shaders using the Arnold standard surface so okay there's my birch that's gone now so let's delete that so here in the hypershade we've got the oak tree shader it's a fall shader let's just map that out it's over yeah so it's a function switch this in here but I'm just gonna rebuild it so you can see it has a tiff image of oak bark and it's going into a ramp and then the out color is going into color why do they run it through a ramp I don't know I guess they are yeah it's not even in the ramp they're putting it into the color gain there must be a reason for that maybe so they can use the ramp to change this because this is going from gray to white so it's probably changing the expression of this from the bottom to the top a little bit so we can do that too we're just gonna copy they have here so we'll just do a i standard surface and we can just pipe this ramp of color in to our base color right nothing fancy and then I can just select the trunk and apply this to hope Sun probably off screen here sorry so I just selected the trunk right clicked on the high standard surface and a assign material to viewport selection right good so now let's look at the AI standard surface and let's call this trunk shader it's very specular let's turn that off and let's just do a quick render to see what we're dealing with here right so that's a bit better it's kind of deceased I'm getting a bit closer here right so it's kind of a wonky tree but this texture is pretty good and it's being repeated through here the UVs of these are laid out nicely so you could even swap in a different texture if you wanted to so if we just look in the hypershade this is just a file node and we could replace it with any texture we wanted so just as an example I'm not gonna bother because I don't want to lose what I got here but you could just swap in something else here Arnold might want this to be raw I'm not sure actually I don't forgive it yeah it's kind of blown out okay should turn up my render here now you'll notice that it's really kind of jagged paint effects is not meant to be the star of the show it's meant to fill in the background I think most of the time and so that's why you get some low resolution types of models we can smooth this of course so we can smooth it just with the on-screen preview and if we render it it'll be better right so that looks better already if you don't want to have it smooth on screen of course you can just like any other Arnold anything rendered with Arnold you can go into the object shape node scroll down to Arnold subdivision and turn on cat Clark and maybe give it to subdivision so now it's not smoothed on screen but when I render it it will be smooth right so that's good now so that's dealt with now the leaves so these are all one object together and if we look at the oak leaves they come in as a fungus well we're gonna do the same thing and rebuild this as a AI standard surface let's just name this leaf we don't get mixed up here and the same thing it's a little more confusing they have this oak leaf texture and then they're running it through a reverse and then a multiply divide and putting that into specular color so essentially what's happening is that they have an alpha channel around this leaf texture so there's a part that is colored can we see it yeah and then the cutout around it and they don't want any specular to appear in the cutout area they just want the specular to appear on the leaf so they're taking out the alpha they're reversing it this multiply divide I don't know maybe it's making sure the numbers are positive I guess and then they are that doesn't make sense I don't know what's going on here and then it's going into specular color so ultimately what they're trying to do just make the specular highlights only on the part that has leaf texture on it and not the part that is transparent let's not worry about that too much so we're just going to take their color ramp again and put it into our base color and if we wanted to take if that's what this is actually doing this multiple this last multiply divide we probably would put that in the specular weight Oh or maybe the specular color here I don't know let's see let's put this on our leaves have to leave selected right-click assign material now because there's a see-through component on this we have to declare that these leaves are not opaque and we do that in the shape node of the object under Arnold turn off opaque and let's see what happens if we render now let's save the file is that working no it's not I forgot one one step so we have to get that cut out information right so here we see from the oak leaf tip going into the transparency of the original fallen shader we to do the same thing but in our case we take that out alpha from the leaf and pipe it into the opacity of the Arnold shader oops sorry let's make this a bit bigger it might be a better way to do this I don't know but since our alpha is a single channel and opacity is a triple channel we can just pipe this into each of the opacity red green and blue and that should work so that means now that the alpha channel is being cut out and we know the pot the non leaf part should be transparent so let's just take a picture so we can compare render again you can already see that's better you can see it's actually taking quite a bit time to render here it might be that these things are reflecting themselves so we could turn off specularity because I don't think it's really doing that much see if that helps is that faster it looks like it might be so that took 9 seconds to render I'm just going to change my render setting so we can see a little more clearly it's gonna turn off my auto detect threads put minus 1 so it airlines 2 so it saves 2 threads for me we're going to oh yeah and change the bucket size to 16 this just means it works on a smaller area so we see this these little things rushing around here working away you can see that's actually pretty good-looking I mean to model this and set this up would be a huge pain so if you need a tree to fill it like an architectural rendering or something this is actually pretty good yeah so the trick is you just have to convert your paint effects to polygons and then you'll probably have to rebuild your shaders it's not hard but it will work work much better if you are using the Arnold shaders alright we'll come back and we'll look at using mash with a paint effects object

Channel: 3D Splanchnic

Views: 29,081

Keywords: maya, paint, effects, rendering, arnold, animation

Id: RWOT4QomaNg

Length: 21min 58sec (1318 seconds)

Published: Fri Nov 09 2018