Foliage render optimization

[abronee]

Hi everyone!

I hope this is in the right forum category for the subject I wish help with. If not, I am sorry..

I am currently doing a scene in Maya with Vray next with quite a few trees with 2k textures and also an opacity map of course. I am currently getting really really long render times, and I would like to ask everyone for tips on how I can optimize it better. This is what I have already done to speed it up:

- Made separate render layers so I can render the trees only.
- Turned of Generate GI with the Vray object attributes node. (Will the receive GI affect also render times? I am thinking its the generation of GI which is quite heavy since its calculating bounce light in between all the millions of pines).
- Lowered texture resolution to 2K.

I have read something about texture filtering and blurring, but its old articles and I can't really find decent documentation on this, at least for Vray Maya (I am open to receive links) - so if anyone would know about this it would be great.

My scene is lid with an HDRI and also a Vray sun.

Also, I am not sure if its the AA taking so long, or the light calculations, perhaps someone could enlighten me on this subject or how to troubleshoot that. (I would guess using render AOV's?)
I have attached my latest render which took a whopping 14 hours on 1920x1133, and I am not even halfway from the end goal. Unfortunately, I don't have the sampling AOV but a lot of pixels were shown red around the pines, even though I set settings quite high.

EDIT: Should also mention that trees are Proxys, maybe that has a saying as well?

Thanks,
Andreas

[fixeighted]

At a glance there doesn't seem to be any reason for a scene like this to take that long.
Is it only the trees that take the time? If so then check and adjust the materials to isolate the issue.
If it's not just the trees then your settings may be off. You can try resetting Vray to default values to see if that helps.

[^Lele^]

Could you share the scene, or parts thereof, to take a look at the settings and shaders?

[damaggio]

Are you using the clip feature in the leaf shader?

[vlado]

It might help to set the opacity mode to "Clip opacity" in the respective VRayMtl. There is some more information here: https://docs.chaosgroup.com/display/...le:Opacitymode

Best regards,
Vlado

[abronee]

I have now set the opacity mode to Clip which helps a bit - I have also changed IM + LC to BF + LC as I find it faster somehow (even with low IM settings). But I feel like I am getting too much blur from this new GI setup (also from the previous setup with the render i attached tbh).
^Lele^ I can't upload it, the zip is too big haha..

[^Lele^]

^Lele^ I can't upload it, the zip is too big haha..

Support can provide you with resumable options, should you wish for them (f.e. an FTP folder.)
We have all the room in the world, if you're willing and able to share the file. ^^
Mail them, and they'll find a way.

[abronee]

Support can provide you with resumable options, should you wish for them (f.e. an FTP folder.)
We have all the room in the world, if you're willing and able to share the file. ^^
Mail them, and they'll find a way.

Who should I mail then?

[^Lele^]

Who should I mail then?

support@chaosgroup.com
Make sure you mention this thread, they'll get me the scene.

[vlado]

The irradiance map will be very slow for foliage indeed. BF+LC should work faster.

Best regards,
Vlado

[abronee]

Thanks ^Lele^ , I hope I can get you the scene soon and thanks vlado for your input as well.

[Morbid Angel]

The render time depends on many factors. One of which is your hardware. If you are rendering on a slower machine, it would explain the long render time. But looking at your scene it should not be taking this long. Are the cpus at 100% when rendering? if they aren't, it could be a sign that the scene has run out of ram. Take a look at that. I would also ask what are your sampler settings? If you have them set extremely high that would also explain the render time. Additionally, the gi is playing very little role in a night scene like this. I would just render the scene with minimum sampling settings and gi off, to find out what is the reason for a slow down and work from there.

[abronee]

The render time depends on many factors. One of which is your hardware. If you are rendering on a slower machine, it would explain the long render time. But looking at your scene it should not be taking this long. Are the cpus at 100% when rendering? if they aren't, it could be a sign that the scene has run out of ram. Take a look at that. I would also ask what are your sampler settings? If you have them set extremely high that would also explain the render time. Additionally, the gi is playing very little role in a night scene like this. I would just render the scene with minimum sampling settings and gi off, to find out what is the reason for a slow down and work from there.

Hi Morbid. I'm on a i7 8700k with 32 GB's of ram. It is basically the trees that add up 90% of the render time - if I had render my layer without trees, its fast.

[dgruwier]

How are your trees made? Do the leaves have individual polygons, and are they set up with 2sided material and reflections and everything?If so there are two things I'd try:

- Reduce the reflection max depth under the Reflection - Advanced panel in your leaf material. Try 2 or just 1.
- Add V-Ray Material Override from the Attributes menu in the attribute editor. Replace the GI and reflection material with a default vraymtl with no reflections or opacity or anything, just a solid color that more or less resembles your average leaf color.

Render before and after to make sure it doesn't affect the look too much. Those tweaks reduce the complexity for the GI without you having to turn it off (which in itself can increase render times, since VRay uses the light cache for optimization). I'd try disabling any GI overrides you have on any objects and resetting the settings to default with GI enabled. See if that does anything. Particularly useful for trees that have been set up with full shaders.

[Karol.Osinski]

You could also changing max transparency in the overrides tab, I believe 50 is default, you could easily go down to 25-30 without loosing much lighting coming through.