Flickering on large environment with high detailed geometry

[Guest tar]

2 hours ago, Skybar said:

I cant remember exactly, but some guys I know had some problems with this like 2 years back. It boiled down to SOPs being in 32bit and Object Level in 16bit (or the other way around). To solve it they moved the geo to origin in one of these spaces and then moved it back in the other. Cant remember the details but I think it was something along those lines. Maybe you know Marty?

I'll have to check but it sounds familiar - probably 32 bit in Sops and 64bit at scene level.

[Mzigaib]

Just an update:

Clipping planes, adjusting them close to the target didn't work jittering still persists.

[Guest tar]

if you upload a tree sample model we can test too!

[Mzigaib]

3 hours ago, davpe said:

i understand that but you said that the same problem persists with even a single tree. so have you tried to unpack that and scatter, say, 10 trees in different distances from the camera? or, another thing to try is to render it as a a geometry procedurals. good for very heavy geo. the point is to find out if it haven't gone wrong by packing the geo.

In the same shot I have trees spread all over the place so some close and others off course far away and the pattern is the same, close ones no problem further ones the jitter problem, I didn't try procedurals thou, it should be the same isn't it? I am using alembics for the geometries anyway.

3 hours ago, Atom said:

My first thought is poor texture or shadow maps. Like anti-alias or mip-mapping.

Are you using shadow maps or raytraced shadows?

I can check for the texture maps, they come from speedtree directly, I am using raytrace shadows.

[Mzigaib]

15 minutes ago, marty said:

if you upload a tree sample model we can test too!

Thanks a lot dude! but the alembics are gigantic and they are animated and varies from 4 up to 10 GB but they are all generated in Speedtree. I really would like that it was possible to send you the files.

[Mzigaib]

Could that be a bug? Maybe i should update the Houdini build

Edited June 6, 2016 by Mzigaib

[Guest tar]

7 minutes ago, Mzigaib said:

Thanks a lot dude! but the alembics are gigantic and they are animated and varies from 4 up to 10 GB but they are all generated in Speedtree. I really would like that it was possible to send you the files.

No probs - 1.5GB takes approx. a minute here upload/download 

[Mzigaib]

Ok there it goes, let me know if you can dowload it.

https://drive.google.com/file/d/0B37nkfFLJRn4U3MzV1FQZGpXZ0U/view?usp=sharing

This is one of the trees that I am using.

[Guest tar]

the tree has too much high-frequency detail in it. A sphere placed at the same distance doesn't flicker.  

[Mzigaib]

Nothing I can do about that, the trees need to be highly detailed because there's going to a zoom from them and to them in other shots.

[Guest tar]

You should render a low level of detail version too, then blend them in Comp - adding temporal motionblur is the key, unless you can render them enormously oversize and downscale.

[jujoje]

My laptop is so not going to handle the scene and away from workstation so can't check your scene, but remember having the same issue with trees from speedtree.

I came to the same conclusion as Marty with pretty much the same solution; ended up creating an LOD on the trees and rendering the leaves as points when they're a ways off and blending which fixed the problem (well not so much fix as workaround...). 

 

 

[Mzigaib]

Thanks for the tips guys I'll try that for sure, I've read somewhere that objects with flat surface as leaves can be a problem and if you give them a thickness is easier to calculate the illumination I'll try that as well.

I wonder if that happens in other render engines as well, anyway thank you guys again and let me know if you got more tips.

Cheers!

[Guest tar]

Octane with 500 samples.

[Guest tar]

PRMan default settings:

[Mzigaib]

It seems that is flickering too right? and I figure that 500 samples is a lot, am I wrong?

But if you compare you are going to see that in my case the trees are much further.

Edited June 9, 2016 by Mzigaib

[Mzigaib]

Here is another test where the tress are static and the camera is traveling slight forward, I think it's a little better that last time but I still get a flicker:

Settings:
Pixel samples: 6X6
Ray variance Min 1 Max 100 Noise 0.005
No diffuse bounces

Things that I've done this time:
Created a clean shot;
Updated Houdini from 15.0.416 to 459;
No other assets besides the tree and 2 lights in the shot;

I am still doing tests, a little bit more before going to Sidefx for help, so any tips would be appreciated. 

Edited June 9, 2016 by Mzigaib

[Guest tar]

4 hours ago, Mzigaib said:

It seems that is flickering too right? and I figure that 500 samples is a lot, am I wrong?

But if you compare you are going to see that in my case the trees are much further.

500 is super low - you should try out Octane demo- I don't have time currently to set it up with instancing and the lighting, but in my quick tests I think is better than Mantra.

[Mzigaib]

I can't use it right now the studio is using mantra for some FX heavy scenes and VRAY for other kind of shots the tools are already in place the problem with octane is that is not going to handle all the geometry that we are going to need and for the tests I did I don't think it is flexible as Mantra but I know it is fast for most cases.

[Guest tar]

yeah - there's 'geofilterwidth' to help with reducing crazy sampling for lines and points, but nothing for thin geo afaik.