raytracting problem.

[bradon]

at some point we had to upgrade our farm to the latest builds so we could DR with our workstations and take advantage of all the sweet upgrades you guys have been making to the software.

at some point something changed and our renders are coming out significantly flawed. I can show a comparison of 3 frames one was rendered with the sep 15 build and one with the aug 10 the other with the june 26th build.

seems like the GI is not calculation correctly in the reflections or that the raytrace depth is somehow getting messed up. anyone have any clue where I might start to figure out what the problem is? only difference is the machines have different versions of vray. older one seems better but notice the render gets progressively more black in the frame.. perhaps when the new features to exit color and mapping a texture there could have caused a problem?

http://i245.photobucket.com/albums/g...omparisons.jpg

[bradon]

still sort of a mystery what happened here but looks like rebuilding the shaders within the newest version helped. I notices we use the overide vray material in the SG group for this specific render. between versions I notice the UI for this has been changed between these versions so that their are checkboxes now for each overide element.

http://i245.photobucket.com/albums/g...bb/Overide.jpg

however I think rebuilding the water shader and the overide shaders in the new environment seems to have worked. will test it on the farm tonight.

[bradon]

still trying to sort the issue out whats causing the water to render different.. on closer look we think it might possibly be a "normal" issue? our normals are flipped inward. so some of the older machines still render fine. but on looking at this render it does sort of look like its rendering the reflections inside out on one machine. even thought we have tried to make the surface double sided and use opposite side nothing seems to make the mesh render correctly. we are going to try to re-export our mesh from houdini and hopefully the normals stay flipped outward when we compute the vrmesh.

[vlado]

It would be best if you can provide us with an example scene to vraymaya@chaosgroup.com so that we can check what's changed.

Best regards,
Vlado

[bradon]

I can set that up for you guys... one quick question is there any way to flip the normals on the vrmesh once it is in the scene? or possilby to export a geo sequence from the ply2vrmesh converter?

edit: I think we sorted the inconsistent problem out, we actually had 2 vrmesh in the scene so that was the cause of the problem. my bad user error once again

[vlado]

ply2vrmesh has an option to flip the normals when converting .geo files. Run it without parameters to see a list of all the options.

Best regards,
Vlado

[bradon]

right but to go in reverse? we have deleted our geo seq. so to output a geo or obj seq from a vrmesh so we can look at it in houdini would be helpfull. also to flip normal on a vrmesh that is already a vrmesh.

[vlado]

Hm, not right away. However, you can bring the geometry back as a regular Maya mesh, and use Maya's tools to flip the normals (there is an option in the V-Ray proxy object to bring in the entire mesh in the viewports instead of the fast preview).

Best regards,
Vlado

[bradon]

this geometry crashes everytime i try to import it, could be that the geo is really really heavy about 2GB because its a water simulation and its animated and maya just cant handle it very well. I tried it on a simple dforming sphere proxy and all was good. our bad for deleting our origional geo seq. show entire mesh helps us get a good look at the mesh and we can see that we have some normal issues going on, but i dont think we can flip the normals with it as a proxy. just looking for extra ways to control our situation better.

[vlado]

It should not be too hard to add an option to the proxy to flip the normals internally, but it means you'll have to update to a newer build. If this is not a problem, let me know and we'll do it; will be much faster than coding a converter to .geo files.

Best regards,
Vlado

[bradon]

wow! super.. you guys are awsome! we just updated our farm to the sept 15th build. its fairly hard for our IT guys to keep track of all the versions and we are worry all the time about renders comming out inconsistent between the versions because of new features or things that might have changed (improvements mostly) but sometimes consistency is better for our deadlines I think for now it is a pain for us to re-export the geo but we will do it because its less of pain than to upgrade our farm. however we would really appreciate that feature when we do decide to jump to the newer nightly. thanks much!!

[vlado]

Ok then. Still, if you get the chance, it would be useful to get an example scene to determine where the difference comes from (if there is still a difference after removing the duplicate mesh).

Best regards,
Vlado