Iray Water
Nyghtfall3D
Posts: 813
With the notable excpetion of pools, I have yet to see a render featuring Iray water that doesn't look like jelly. Case in point, this product by SickleYield:
The first three promotional renders highlight the problem:
http://www.daz3d.com/rigged-water-iray
Can't the shader be tweaked somehow to create a more realistic effect?
Post edited by Chohole on
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Comments
i think the shader itself is quite good, but i know what you mean. I think it looks like that because of the geometry, not the shader. The 'volume' of the geometry makes it look more solid than water really would in real life. It makes it look thicker, makes it look like it has higher viscosity than water.
Ah. That makes sense.
Thanks.
@Nyghtfall I forgot to add that the right shader does make a difference in Iray. I have that set and I used a different shader with much more translucent effects. No offense to Sickleyield as it is a great prop and the shader is good, just not quite the look I was going for in this one piece I was working on. I'm on my way out at the moment, but when I get back I'll see if I can track down that scene and find out which shader I used.
SY's models are awesome, I do confess that I adjust most materials I use on everything anyways, LOL
I think the key to water materials in Iray would be to tone down the reflections some. That is what breaks the realism for me visually.
Some other tips would be: use a slightly lower Index of Refraction then what would be listed as "Real World" - This will "clarify" the water a little.
As with everything, lighting will play a huge role in how the refraction and reflection effect the look of the water too.
Mec4D's volumetric water shader might be worth a try.
I agree iray water looks like goop. I think making realistic splashes really have to be done postwork. I haven't found a splash utility or prop that looks quite like it should.
My free shader:
Also shader I'm working on:
http://willbear.deviantart.com/art/WTZ-Choppy-Ocean-608293789
Bump and normal maps can really help make the surface more interesting/complex.
I think its mostly a geometry thing. Real world moving water has spray bubbles, etc. a lot of things that would end up using a lot of geometry
For Iray, if the water has volume, you MUST use the Water shader (or similar) not one of the Thin shaders (water-Thin)...those are for single face 'thickness' items posing as a volume.
Another thing...caustics. Water has them...even if we don't pay much attention to them, when missing the lack is noticeable. The caustic sampler should be ON, if water is going to be a focal point of the render (it WILL increase render time).
Also, Iray has a spot to input an Abbe number. While we don't really think of water when we think of dispersive materials, it is...and dropping in the Abbe number for water does help.
Bubbles...or more precisely, the lack of. Almost all water has noticeable bubbles (more so when they are missing).
Ripples...most water, except stuff sitting in a glass, isn't perfectly smooth, but most water props are much smoother than real life.
The other thing to consider especially in iray is a decent normal map. This render i did a couple days ago for example i have been using the same Normal map for all my water renders for quite some time i just mess with the tiling depending on the situation.
Daniel
Bingo. People are often ready to point the finger at lack of realism, but until I can afford RealFlow I pretty much have to sculpt water manually (and duplicate out all those droplets manually, etc.). Blender's fluid sim does not produce good droplets or spray and neither do most programs. Even with the geometry I did the product is pretty resource-intensive. That wouldn't stop me selling a realistic water sim even if only ten people could actually render it in under 12 hours, but like I said, RealFlow's expensive. ;)
I think one of the problem with rendering moving water is that you'll see it "frozen in time". In real life your eyes can't follow the motion accurately so you get a 'blur'. But have a look at those photos with brief shutter times, the water in them looks more or less the same, depending on lights et cetera.
And what about waterfalls 3D models? Has anybody seen a good one?
I think that with a good model, as far as geometry is concerned and with an appropriate bump and displacement map, some pretty good results can be achieved as long as you do have the patience to tweak the shader to your satisfaction. So what do you think of this choppy sea? Straight iray render, no post.
If you look what the OP said, his issue with unrealistic water was not with large, flatish water, that you see in lakes, pools, seas etc, but with smaller bodies, like the spray from fountains, or the stream coming from a tap/shower. As stated by many people above, the issue here is with the geometry of the water object, not the shader used in the render.
Yep 3CPO, that is some good looking water there and it holds up at full size too.
Wateris the nemesis of all, as it has movement, varied geometry and lots of light issues!
@3CPO Great job. Thanks for sharing. I love the reflection of the sky and extra detail the bump adds to the waves. Grab Casual's surf foam model and shader and you have it made. With water that choppy its bound to leave some foam from striking the rocks.
Definitely among the better examples.
How much flexibility do you have for altering the depth? Is this done as a single volume, more than one volume, something else?
One thing that is really bothering me right now is the water shadows. Besides caustics, water also casts shadow due to its threshold angle that captures lights on its borders. That is one huge thing that I don't see when creating sweat or water droplets with the water shader... So far haven't found a way to do it. Does someone know how to make it happen?
Although I haven't tried it, from a purely scientific point of view, it's the refractive index that is responsible for the shadowing you speak of. Despite being a PBR, Iray's RI figures aren't exactly as should be expected (again, from a scientific point of view); and then there's the fact that waters with impurities all have marginally different RI's but mostly still around 1.33.....
Colour also effects water's RI, as does temperature (yes, that means water at the poles has a different RI than water in the tropics).
So in other words,we're screwed keep on tweaking.............
...ouch, indeed. Is it a standlone programme?
...water, another one of those items, like skin, hair, and cloth draping, that can easily break realism in Iray. I have one Iray scene which includes water, however it is in a courtyard reflecting pool so it doesn't involve much in the way of surface motion.
Good observation kyoto kid and I'd like to add that water shaders, just like skin, will look differently depending on the environment it is in. So there is no one-size-fits-all solution and no water shader that will suit every environment.
IMO water shaders that incorporate texture maps don't work very well with Iray. And all bodies of water lager than a glass of water will need some sort of displacement/normal map to look realistic, and adjusted to suit the effect you want.
...for that scene, I created a custom shaped primitive for the pool in Hexagon to give it "substance" then adjusted the opacity, refelctivity, refraction, fresnel angle, and colour
Here is the pic (click for larger).
Yep. It can output animation to programs in several formats; for DS it would be obj (it has a direct bridge to Cinema4D but not Daz Studio). For a commercial license node-locked to one computer it's about $1000. At present I have to set that behind VR equipment for Unity on the priorities list (and I just spent almost $700 getting a GTX 1080 so right now the Oculus is still a list item, not a "buying right now" thing).
I make a high income for a Published Artist and about a median income for the Top 30 list from what I've gleaned from other people. So if I find something expensive, it's probably expensive for most PAs that aren't in say the top 15.
OOps,
you've got a lot of those 45° artefact patterns on the ground. Happens always in iRay, if the texture pic is way too small.
In my scenes I use the iRay Uber water shader and apply bump of a texture from an old set.
--> http://orig15.deviantart.net/721f/f/2016/320/a/5/fun_at_the_pooldeck_by_andysanderson-daondbr.jpg
Tested a SY shader (first pic), a MEC4D shader (second), and google image of real water (third). They all look pretty good, like real water -- to me at least.
I imagine the best shader will depend on the lighting. I just used a terradome HDR.
I really like Will's water shaders. I think they are great.
Here I've used his "ocean" shader.