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Render large scenes (How to save RAM?)

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  • Render large scenes (How to save RAM?)

    Hi,

    some tricks can be done to save RAM and render complex scenes:

    * try to find lower Rhino mesh settings to keep the polycount of the scene low, also try object based mesh settings

    * convert all NURBS to meshes and delete the NURBS geometry from the file (for best mesh result buy MOI3D - the fastest and cleanest NURBS mesher)

    * use a 64 bit OS and Rhino should allow to use approx. 3.6GB RAM instead 1.6GB only. If 4GB are installed, Rhino could crash at 3.2GB, if 5GB are installed Rhino should use until 3.6GB (tested with XP64).

    * try to keep your textures small, large textures needs much RAM

    * other great working trick: after the render button is pressed and the scene is loaded to the Vray engine, try to open an empty Rhino scene. A button script from here do it for you
    http://asgvis.com/index.php?option=c...0&topic=2013.0

    * use Rhino blocks for repeating geometry - since VfR dosn't support instances yet it helps a little only, but some times it help to avoid the crash

    * use the vrimg output - can help a lot for very high res (last I rendered 20.000x16.000).
    Here can be found the conversion tool:
    http://www.spot3d.com/vray_downloads/vrimg2exr.rar
    Here can befound an tool for the conversion tool:
    http://www.chaosgroup.com/forums/vbu...s-(SP2-update)
    ... and here the info page:
    http://www.spot3d.com/vray/help/150S..._vrimg2exr.htm

    * some times it helps to start a fresh Rhino task and start the rendering immediately

    And for Rhino v3 user here a patch for more available RAM:
    http://forum.asgvis.com/index.php?to...19093#msg19093

    * Edit dec 2009: my spawners crashes with a high RAM uage (higher than 3GB). At the process window I found, that one texture was loaded extrem often. The reason was, that the texture was assigned to some object witn exploded surfaces (because the mapping control). After I extracted the rendermesh, hide the orginal geometry and joined the mesh faces, the texture was loaded only one time anymore. Wow, the RAM usage was down at a few hundred MB.
    Conclusion: try to join objects with same material, if you like to save RAM. If a texture is used at hundred independent objects, than the texture is hundred time loaded.
    General - it seems to be, that the usage of many textures can be a problem for DR. For example the rendering of a libray with many books/textures need 1GB RAM at the master machine and 3.2GB at the slave machines. I hope it's a bug that can be fixed in the
    future.

    * Edit feb 2010: increase speed of displacement - I found, if I use several objects with the same displacement material and the render times are extrem slow, than it helped to extract the rendermesh, delete or hide the original NURBS and join the meshes. The joined meshes keeped the mapping and the material. The render speed was strong increased. (if different mapping types are used and join should destroy it, than it helps to export the meshes as obj and reimport it - that "bake" the UV to the meshes and join is 100% save).

    *Edit Feb 2011: displacement can be much better used for large architecture exteriors (grass) if the displacement amount is set to 0, the LC calculated and saved and than the rendering is started with disp amount 1 and read of the cached LC. So the LC pass is much faster calcualted (hours vs. minutes).

    * Edit april 2011: today I found, that disabling "filter maps" can save a lot of memory. So I disabled it, calculated LC+IR and saved the passes for later use. The final pass was rendered based on the cached GI and "filter maps" enabled. So I got the an image rendered that crashed before.

    ++++++++++++++

    Some other hints against crashes:

    "I'm using Vray for Rhino as well. I had similar problems in the past... usually
    it is due to specific geometry in your scene (or texture!). What I usually
    do is to make sure there aren't any duplicated objects also no bad objects.
    You can also use the "purge unused information" rhino command - it cleans
    lots of autocad crap if you have imported your file from there.
    With 5-10 small testing renders you can exclude some objects and isolate
    the problematic one! Once you get it- try changing its material, and if still
    goes bad just re-model it "
    http://news2.mcneel.com/scripts/dnew...m=381875&utag=

    Also be careful with JPG:
    "Most of the time use jpeg images for mapping. It turns out that there are (at least) 3 different kinds of jpeg formats: Baseline (Standard), Baseline optimized and Progressive. Using anything but the standard Baseline kind of mapping for lighting, diffuse, bump or whatever would cause Vray to crash instantly on rendering."
    http://www.chaosgroup.com/forums/vbu...700#post538700

    Good luck,
    Micha
    Last edited by Micha_cg; 28-12-2011, 02:16 AM.
    www.simulacrum.de - visualization for designer and architects

  • #2
    Re: Render large scenes (How to save RAM?)

    ... danke for repply Micha

    I just wanna ask you somethings :

    Faces for rendering are the same with or without NURBS curves - why should I delete`em ?

    What is VRimg ?

    regards

    Comment


    • #3
      Re: Render large scenes (How to save RAM?)

      What Micha's techniques are trying to do is clear as much unneeded information from memory so that V-Ray can do its thing. When you have a scene in Rhino the NURBS geometry is in memory as well as the render mesh that is used to display it. When you render V-Ray then has a copy of that render mesh. So that makes it a total of 3 "copies" of the same geometry.

      By extracting then mesh from the NURBS geometry and deleting the NURBS, you've effectively removed one of those "copies" automatically. One of Micha's later suggestion of opening up a new scene once the render starts removes the second "copy" from Rhino and only V-Ray has the scene geometry.

      I explained VRimage in the previous thread...let me know if you have more questions.
      Damien Alomar<br />Generally Cool Dude

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      • #4
        Re: Render large scenes (How to save RAM?)

        thanx guys
        you are a lot of steps ahead.
        I`ll try the things you advice me.

        Comment


        • #5
          Re: Render large scenes (How to save RAM?)

          I try meshing and deleting NURBS but situation becomes worst - Vray blocking even faster.
          Before change my OS and increase RAM more 2x2GB wanna ask something : Is that enough to render 248mb scene ?
          Vray crashes at "Building geometry table" ( or something ) , before render even starts - is that harder part of the rendering ?

          regards

          Comment


          • #6
            Re: Render large scenes (How to save RAM?)

            Best check your polycount (at my render tool thread is a polycounter) - maybe your manual meshing caused a to high poly count.
            www.simulacrum.de - visualization for designer and architects

            Comment


            • #7
              Re: Render large scenes (How to save RAM?)

              New way to save a lot of RAM in some cases. See last edit of the first post.
              www.simulacrum.de - visualization for designer and architects

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              • #8
                Re: Render large scenes (How to save RAM?)

                First post updated
                www.simulacrum.de - visualization for designer and architects

                Comment


                • #9
                  Re: Render large scenes (How to save RAM?)

                  Hm, i'm using rhino v4.0 with sp 6 i have win xp, amd athlon II X4 630 2.8ghz, 4gb ddr3 1333mhz, ati radeon 4850 1gb and my rhino crash with 1.6/1.7 gb?! i knows, this model is heavy (something about 165mb) but i haven't any displacement or something, i have only one or two textures with bump and that's all, any chance to change this?
                  www.maciejnowak.eu

                  Comment


                  • #10
                    Re: Render large scenes (How to save RAM?)

                    "* try to find lower Rhino mesh settings to keep the polycount of the scene low, also try object based mesh settings"

                    sorry, but how i do that? When we use your Toolbar button that opens a new archive with only the meshes, doesnt the scneane ready to be render? or we must "lower Rhino mesh settings" before?

                    Thanks

                    Comment


                    • #11
                      Re: Render large scenes (How to save RAM?)

                      You must set the mesh settings in your original file with the NURBS data. The toolbar button script extract the render mesh (that based on the mesh settings), export the render mesh and lights for rendering. In the new file are meshes only and the meshing settings are not used anymore.
                      www.simulacrum.de - visualization for designer and architects

                      Comment


                      • #12
                        Re: Render large scenes (How to save RAM?)

                        VRimage links added to the first post. I rendered my biggest rendering today - 20.000x16.000 pixels.
                        www.simulacrum.de - visualization for designer and architects

                        Comment


                        • #13
                          Re: Render large scenes (How to save RAM?)

                          "filter maps" trick added today.
                          www.simulacrum.de - visualization for designer and architects

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                          • #14
                            crash hints added today
                            www.simulacrum.de - visualization for designer and architects

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