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  • vrayScene nodes issues

    Hi,

    First let me point out that having the ability to bring fully shaded assets from one software to another is amaizing and super valuable.
    I'm trying to get some assets from 3dsMax to Houdini using vrayScene exports but I'm running into some issues.

    I setup a small test scene to examplify the transfer from 3ds Max to Houdini, you can also find it attached in the next post (exceded 5 attachments).

    When using the vrayScene with no modifications it rendersare close result in Houdini. There is some differences in the noises, but the size and color corrections are there, but the bump on the gold bix is bugger and the displacement is a bif off in the red torus.
    Left 3ds Max, right Houdini.
    Click image for larger version

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    The big issues start when scaling the vrayScene data, since 3ds Max is in Centimeters and the cata when imported is in meters so it needs to be scaled by 0.01 in Houdini to match to the rest of the data used in Houdini.
    In this example I had to turn off displacement as it was taking over the whole scene. But also every paramenter that was size based (vray dirt, displacement, vray color2bump and vray edge txt) are all incorrectly scaled and still rendered at the original size:

    Click image for larger version

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    And with displacement On, just for the kicks:
    Click image for larger version

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    And the last example is when unpacking the vrayScene using the "unpack to polygons" in the import tab of the vrayScene node.
    When unpacking, the materials won't work anymore as you can see in this image:
    Click image for larger version

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    With all this exposition out of the way, my questions are:
    - Can we get a scale parameter in the vrayScene node that scales the data and scales the size based materials/textures/displacement accordingly?
    - The scale issue can be fixed by scripting a function in 3ds max that runs over the parameters we need to scale before exporting, but this is a bit cumbersome and would be much easier to just do it on import. Or is there any hidden way to do this in the vrayScene node?
    - The unpacking of the materials seem to be quite broken, when inspecting the unpacked materials seems that the 3dsMax Image and noises are missing, I can see why that is as they are 3ds Max specific nodes, but they seem to work inside the vray scene, so vray knows how to read them. Is there anything that can be done to improve this? or to maybe give us an option to read material files only and apply them to geometry (eg: assign vrayScene material to an alembic geo)?
    - Why doesn't the vrayScenes work on the texture baker? I tried using a vrayScene as the geo for the texture bake but it didn't work, is this something that can be fixed/added?


    Best,
    David.
    David Anastácio // Accenture Song - VFX
    https://www.accenture.com/us-en/serv...visual-effects

  • #2
    Example scene attached to this post.
    Attached Files
    David Anastácio // Accenture Song - VFX
    https://www.accenture.com/us-en/serv...visual-effects

    Comment


    • #3
      That's unfortunately quite a huge can of worms We've had varied success with different assets but far from a robust solution Our hopes are now in USD, for cross platform shader descriptions and assignments.
      Hristo Velev
      MD/FX Lead, Bottleship VFX
      Sofia, Bulgaria

      Comment


      • #4
        Originally posted by glacierise View Post
        That's unfortunately quite a huge can of worms We've had varied success with different assets but far from a robust solution Our hopes are now in USD, for cross platform shader descriptions and assignments.
        Yes, USD might be the holy grail, we are hoping for the same here, but until then we need a more imediate solution for ongoing projects.
        For the most part the vrayscene works, it's the scaling it that has some issues.

        Best,
        David.
        David Anastácio // Accenture Song - VFX
        https://www.accenture.com/us-en/serv...visual-effects

        Comment


        • #5
          From my (limited) experience writing scale-aware importers in Maya, solving this general problem gets tricky fast. I don't think USD attempts to do anything in this regard either, currently? (apart from encoding some simple scale/upAxis-related metadata).

          Would be nice to have it "just work" of course .
          Last edited by Dan Andersen; 30-11-2020, 06:04 AM.

          Comment


          • #6
            Originally posted by Dan Andersen View Post
            From my (limited) experience writing scale-aware importers in Maya, solving this general problem gets tricky fast. I don't think USD attempts to do anything in this regard either, currently? (apart from encoding some simple scale/upAxis-related metadata). .
            Our current fix will be to change the necessary shader values on export (3ds max) as this will be simpler and not scaling the data is not an option, we can't have 1 asset in centimetres (max scale) and the rest in a different scale.
            Yes, USD in it self won't do anything, it's the same as slapping a transform node to your data right now, the render engine will look at the scale value and scale the shaders wrongly.

            Originally posted by Dan Andersen View Post
            Would be nice to have it "just work" of course .
            That's all we want
            Getting a scale parameter in the vrayscene node would go a long way specially if the shader values would then be correctly scaled too.

            The ability to transfer assets from a 3dsMax or Maya pipeline is a major Ace for V-Ray, but it needs to work.

            Best,
            David.
            David Anastácio // Accenture Song - VFX
            https://www.accenture.com/us-en/serv...visual-effects

            Comment


            • #7
              Needs lots of work I'd vote for a generalized solution, these piecemeal options take up resources and are quickly outgrown
              Hristo Velev
              MD/FX Lead, Bottleship VFX
              Sofia, Bulgaria

              Comment


              • #8
                Originally posted by glacierise View Post
                Needs lots of work I'd vote for a generalized solution, these piecemeal options take up resources and are quickly outgrown
                By generalized I assume you are talking about USD, right? Dump the vrscenes and invest in USD, I'm all up for that one, but I need it now for a project, so vrscenes it is.


                Speaking of needing it now, Gosho.Genchev and bdancer, there are some issues with the vrscenes at the moment, I mentioned some of them before, but we bumped it a bigger one now.
                When selecting the vrscene node or rendering a vrscene locally Houdini spends quite a long time cooking the vrscene before starting to render, this is specially bad with quite a few vrscenes as it goes 1 by 1 cooking something. Example, the same amount of geo in alembic form takes 10 seconds to first pixel, vrscene 5 minutes, and this was before it started loading textures and shaders, just Houdini cooking. We can also see the ram usage go up quite a bit during this cooking, it looks like the vrscenes are getting read for some reason, this also happens on the farm when we generate the vrscenes to render, the alembic file peaked at 3Gb and the vrscene file peaked at 51Gb (single vrscene with 2Gb and lots of objects in it).
                Like I said befire just selecting hte vrscene node in SOPs makes houdini stop and cook it for a while, we were thinking this was because it was generating the "Viewport Preview", but turning that off doesn't help much, still slow. And setting the "Proxy Preview Type" to Bounding Box also has no effect.

                Can you guys give us some feedback here please, how to improve this or if this is a bug?

                Best,
                David.
                David Anastácio // Accenture Song - VFX
                https://www.accenture.com/us-en/serv...visual-effects

                Comment


                • #9
                  Another example here. Subnetwork with 241 geometry nodes, and each geometry node has a vrayscene node inside set with a render flag and null set with a display flag.

                  Exporting the render scene from the ROP node takes 9m22s, this was after opening the scene and nothing was rendered before.
                  The second export, done right after the first now takes only half a second. This is because all the vrayscene SOP nodes were valuated and cached during the first export.

                  Plus ram usage shoots up during the export, which indicates that the data inside the vrscenes is getting accessed.
                  Click image for larger version

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                  Also, we noticed that there is a VRMat node we can use to load the materials, but it doesn't seem to work with VrayBlend materials so all our shaders transfers fail.

                  We also tried making all geo into VRay proxies first, but the problems persist with the vrayscene node cooking for a while, high ram usage, etc. But those "Proxy Preview Type" controls seem to work with the vrayproxies inside the file, but they cook and load for quite a while even when set to "Bounding Box".

                  Best,
                  David.
                  David Anastácio // Accenture Song - VFX
                  https://www.accenture.com/us-en/serv...visual-effects

                  Comment


                  • #10
                    Same thing happens with volumes in packed disk primitive mode - it takes time and RAM to export the vrscene, despite vray not needing to read the volume
                    Hristo Velev
                    MD/FX Lead, Bottleship VFX
                    Sofia, Bulgaria

                    Comment


                    • #11
                      Originally posted by glacierise View Post
                      Same thing happens with volumes in packed disk primitive mode - it takes time and RAM to export the vrscene, despite vray not needing to read the volume
                      Yes, that's correct, and we pointed that out in another thread with no answer until now.

                      https://forums.chaosgroup.com/forum/...port-with-vdbs
                      Last edited by david.anastacio; 07-12-2020, 01:25 AM.
                      David Anastácio // Accenture Song - VFX
                      https://www.accenture.com/us-en/serv...visual-effects

                      Comment


                      • #12
                        Hey David,

                        We are looking into the issue. I apologize for not saying anything but ... there's really not much I could tell you at the moment. I'll ping you as soon as I know more.

                        Best regards!
                        gosho.genchev@chaosgroup.com

                        Comment


                        • #13
                          Originally posted by Gosho.Genchev View Post
                          Hey David,

                          We are looking into the issue. I apologize for not saying anything but ... there's really not much I could tell you at the moment. I'll ping you as soon as I know more.

                          Best regards!
                          Thanks for the reply, we'll wait for the updates. Small question, are you guys also looking into the VDB issue we pointed out in the other thread?

                          Best,
                          David.
                          David Anastácio // Accenture Song - VFX
                          https://www.accenture.com/us-en/serv...visual-effects

                          Comment


                          • #14
                            Hey David,

                            yes, we've known about the instanced VDBs for a while - one of the developers was looking into it but did not have much luck figuring out the root cause. As there were more urgent tasks, we moved on to them.
                            We'll look into it again.

                            Best regards!
                            gosho.genchev@chaosgroup.com

                            Comment


                            • #15
                              Gosho.Genchev thanks for the clarification.
                              The VDB issue is quite big actually, it makes it look like you can't have more than just a very few number if volumes in your scene and that leads to coming up with convoluted workflows to split the scenes into smaller chunks.

                              Best,
                              David.
                              David Anastácio // Accenture Song - VFX
                              https://www.accenture.com/us-en/serv...visual-effects

                              Comment

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