Tree Populations Shifting/Flickering

[Lynx]

Long time lurker, first post.  I am working on an TG2 animated intro to a documentary film where we fly across a virtual Washington State from Mt. Rainier over Lake Kaches and Mt. Stuart down into the Leavenworth area.  Thanks in large part to the great info I've gleaned here, I have managed to get a very realistic landscape with the qualities of light and atmosphere the director is looking for.  I've set the flight paths and tested everything to be satisfactory, except for one thing that may prove to be catastrophic if I can't get it sorted out. 

When the rendered frames are strung together, the trees (especially those in the distance) move about and look like an anthill teeming with activity.  I think it is that the tree shifts in position or shape rather than just a lighting issue, but I'm not100% sure.  I found another thread that seems to deal with the same issue (http://forums.planetside.co.uk/index.php?topic=8698.0) and have tried all suggestions therein, with no luck.  (Though, I have not done anything with PoseRay, and hope to avoid it.)

I am using Xfrogs plants .tgo objects, and have tried a couple of different populations (Ponderosa Pine/Douglas Fir) at different levels of quality.  I took advice from different threads and have use all kinds of different settings for GI detail and sample quality (1-3), AA (6-11), detail blending (0-1), blur radius (15-800), pixel filters, etc. with no change in results.  I have v2.1 (build 2.1.18.1) on Mac computers.

Color the filmmakers and me extremely frustrated.  Any help you can give me in getting the trees to stop moving would be greatly appreciated.

[RArcher]

Do you have the tree populations bounding area animated to move with the camera, or is it a static population that the camera moves past?  Are you doing any restricting of the populations with distance shaders that are attached to the main camera that is moving?  Do your populations get recalculated each frame?  These are a couple things I can think of off the top of my head that could potentially cause the populations to shift around if in fact the tree positions are moving.  As to GI or lighting flickers I'm afraid I can't be of much help.

[Lynx]

Do you have the tree populations bounding area animated to move with the camera, or is it a static population that the camera moves past?  Are you doing any restricting of the populations with distance shaders that are attached to the main camera that is moving?  Do your populations get recalculated each frame?  These are a couple things I can think of off the top of my head that could potentially cause the populations to shift around if in fact the tree positions are moving.  As to GI or lighting flickers I'm afraid I can't be of much help.

Many thanks for your reply.

Static population. No distance shaders attached to the camera.  Populations not recalculated.  I don't have "clip to camera" checked.

[Tangled-Universe]

Can you show a couple of frames to illustrate the problem?

Martin

[cyphyr]

The populations should be stable, I think its more likely a terrain issue. Try a render of the frames where the trees pop in and out but without the tree populations. Look closely to see if there is any terrain popping. If so this may be the reason why the populations appear to be shifting. To fix this try upping the "Detail blending" to 1 or 2 and also look at the "Displacement tolerance" in the "Planet" node, try a higher value.
Hope this helps
Richard

[Lynx]

Can you show a couple of frames to illustrate the problem?

Hope you can get a sense of what is going on from these 2 sequential frames.  When seen in the animation it really looks as though the trees are moving about independently like a hill of ants.

I appreciate the suggestions, Cyphyr.  I will try making those adjustments and see what happens.

Thanks for your help.

[Dune]

Just a wild idea; perhaps it's the specularity on the leaves that changes with camera angle...

[Kadri]

Try a render with a static camera to pinpoint the problem.

Does the sun move in your shot?
I don't know the animation version , but look at settings that shouldn't be animated without your knowledge that would cause such flickering .
Do not go too far away from the default viewpoint. You may get rounding errors  with TG2 (that any kind of other 3D software too have , so far i know).

[Oshyan]

There seems to be quite a lot of noise in the trees in general, which might initially suggest an antialiasing issue. But you say you've tried it at up to AA11 which should be more than sufficient to get at least better results than this. Are you using Raytrace Objects? What antialiasing filter is in use? Also, have you done any close-up renders of these trees? I almost suspect a texture transparency issue from the white specks I'm seeing in the trees, which seem to move around between frames. Either that or perhaps you have a significant specular effect?

Without seeing the TGD it's all really just speculation, but hopefully one of those ideas gives you a starting point for further investigation.

- Oshyan

[Upon Infinity]

Maybe I've missed something in the thread, but you don't have the 'repopulate every frame' checked, do you?  I don't have the animation version, so I'm just speculating.