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Posts posted by elecstorm

  1. Hi! Is there a way to get the name of rendering object in CVEX with Volume Procedural? Like this is done using renderstate?

    I want to use one CVEX for some objects and change filename parameter in it depending on the object.

    Now I use shared CVEX from Vopnet with Filename parameter on it, but it have some limitations for me.


  2. 10 minutes ago, LaidlawFX said:

    Good luck with your bug submission.

    Out of curiosity how are you cloning Houdini to the network? Is Houdini installed per a node, per a common software server, or on the workstations? Generally speaking Houdini as a whole is pretty "low level" i.e. Houdini Engine vs Houdini (FX, Core...) Also maybe it could be the format you are writing too. If it uses a third party writer like FBX as opposed to .bgeo there is a limit to what they can change in that type of code. Make sure you give SideFX a good repo, otherwise they'll only be able to help so much.

    Houdini installed per node and on the workstations. We almost always use bgeo.sc.

    8 minutes ago, malexander said:

    You could be running out of file descriptors ("Too many open files"). On Linux, you can run 'limit' (or ulimit) to see how many files can be open at once. On my system, it's 1024 by default.

    Which OS are you running?

    It's debian 8 Jessie, on blades, workstations and on the old storage. The newest storage is running scientific linux with custom build. We will check the descriptors limit on the storage, but the descriptors are not limited in my system.

  3. 5 hours ago, LaidlawFX said:

    Not really. You should submit a bug to SideFX with an example scene encase there is a bug. Especially with as much details about your system setup as possible. It could be a fringe case with your hardware setup. If you really don't believe it's the hardware, it could be competing software or your farm that is grabbing your nodes access, i.e. Nuke stomps on Houdini, or your farm software is not sophisticated enough Qube vs Hqueue. It has been a while since I ran into that issue, but the last few years I've gotten to work on very corporate data server hardware. 

    LaidlawFX, thanks for the answer. I really think it's software problem. Different storages, different blades. Nuke creates the same load on the storage, but we don't see any data loss. I was hoping that there is a low-level setting in Houdini for writing geometry files.

  4. Hi!
    I have a strange issue. When I write many files at the same time, some of them breaks. It can be 200-300 files simultaneously size of about 10 Mb, or 70-80 files of 100 Mb - I have the same result: files exists, but 5-10% raise read error in Houdini. They have a normal size or less than normal on the storage.

    I tried this on the old storage and on the newest storage (with perfect access time, speed, caching etc) - the same result. Houdini 16 behaves just like Houdini 15.5.

    When I starting write this files, we have write errors on the storage from other software like Nuke or just write files from the OS.

    Another picture is not observed: when we write hundreds exrs from nuke - there is no file breaks on the storage. 

    This occurs for many months, and I think the reason is in the method of writing files from Houdini.

    Is there a technology to change the method of writing geometry from Houdini (flags, variables)?

  5. Hi!

    Is there a way to bake a volume to point cloud during render?

    I did it for polygons by pcwrite function and by micropoly mantra with uniform measuring (1 point for 1 primitive).

    But if I do this with any volume shader - pcwrite does not work after pbrlighting node (as part of compute lighting node, and I did pbrlighting manually to get Cf): rendering freezes.

    I want to get point cloud with Cf color for each voxel.

  6. Ok, I found this way:

        except hou.Error, ex:
            print ex.instanceMessage()

    It works in the python shell, I have not tested it with the hython. But I don't understand this exception (I found it somewhere):

    except hou.Error, ex

    "hou.Error, ex" - It's not definition (because of comma). So, what is it?

  7. Hi! Is there a way to catch Mantra error in python script?

    I want to implement something like this:
        hou.node("/out/mantra").render((1, 1, 1))
    except error:
        #launch manta again or something else...
    print "Frame " + str(1) + " was rendered"

  8. I'm not sure I understand. These "artifacts" are the result of computing the gradient using the repeated boundary. So they're basically the "right" gradient values for a repeated volume, and you've indicated that your purpose is to get a infinitely repeated volume. Maybe just want to make sure that the borders of your volume to "wrap around" nicely?

    It is strange, because source volume in SOP level also has repeate border type (and volumegradientfile sample it correctly).

    Hip: https://www.dropbox.com/s/22z2wccgjbbfhx9/gradient.hipnc It's hard - with locked volume.


    Now I use two fields: one with repeate border for sample this field out of it's boundary. And the same volume with streak border to calculate the gradient field. But I want to understand why it's happeinig.

  9. Hi! I want to calculate gradient field in dopnetwork. It works perfect, when I do it in gasFieldVop using volumegradientfile node.

    But when I do the same gradient using gasAnalysis in gradient mode, I have some artefacts on the border.

    How can I solve this problem?



  10. Group the pieces with connectivity/partition, then delete based on group. Or they should have a piece primitve attribute you can use.

    Ok, deleting pieces is not problem, but time offset will not work, because each piece will have to be frozen separately.

    Here is an example. Fracture object's peaces are deleted during the simulation, but they are deleted from the scene also...


  11. How about using a switch DOP with a null in the second input. Then just freeze the last simulated frame back in sops with a Timeshift sop?

    I attached a simple example.

    It's fine solution, thank you. I can use delete-node instead of swtich. But freezing object by timeshift works with individual objects only. What about fractured object with hundreds of pieces?

  12. Hi All!

    I have a question. There are many objects in scene. I need to simulate some groups of them in few frames (about 1-2 seconds) - using DOP like a conveyor of sumulation.

    I need to add objects to DOP and delete them during the simulation. Node "active value" works fine, but incative objects anyway slow down simulation's speed.

    Is there any solution to remove objects from DOP during simulation? And freeze object's last state in scene.

  13. Make sure to bring the object in as a RBD Fractured Object, this works most of the time.

    If that does not help set up more sub-steps or try to create a glue constraint controlling object activation....

    Or if it needs to be a fast sim(look development) the scale each piece down a bit, so that your edges do not touch, simulate the scene, run a for for each on the imported pieces.

    In the foreach create a point in the center of each simulated piece, then bring the original not simulated pieces into the same for each and copy them on the new point.

    This should speed up your workflow a lot and still give u decent results, especially if you add debri systems and dust.

    oh and to create the debri system simply scatter points on the inside group of the fracture objects and bring them into a popsop.

    in there you can give the point what ever behavior you want to, and then copy your debri geo with a stamp function onto the points.

    check out the cmivfx tutorial on fracturing....

    it is not the best, but has a very strung foundation



    Thanks for your answer. I think, create-clusters-option makes concave pieces. That's why they explode. I turned it off, and simulation works fine.

  14. Can I add my questions here?

    Why are manualy-fractured objects can explode after the start the simulation? (see attachment)

    How to procedurally separate pieces for static (outside of the fracturing radius points) and kinematic RBD solvers?