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About phong

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  • Name
    Nhat Phong
  • Location
    Berlin, Germany

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  1. Deep AOVs broken

    When rendering with deep (EXR or RAT) all the extra image planes that involve lighting have colors that are off (magenta or green). Also when viewing in the composite view in Houdini those AOVs look broken as in each channel seems to be offset. In nuke you can see the AOVs, but the colors are all off. I double checked that there were no double .red & .r channels in Nuke. Anybody ran into this?
  2. Hi! I was wondering why when having active RBD objects in a passive RBD container start to gain very aggregated velocities when the passive deforming RBD starts moving around. I was expecting to have pretty much a box with some objects in and the box moves around. But when the box moves around all RBD contents inside would just go crazy and pop out like popcorn. Tried multiple collision substep settings, played around with density ratios, bounciness, all kinda the same result. I'm using bullet rbd solver for that. Thanks! Nhat
  3. Hi! I've created a VEX code that I've wrapped as an OTL digital asset with a nice parameter interface - all based off a VOPSOP. Now I want to add a parameter to the VEX code and have that parameter be part of my nicely arranged parameter interface. However when I added the parameter to the function definition and created an identically named parameter through the type properties interface, the parameter doesn't change the behavior of the code at all. Now when I check the "Get Properties from Vex Code" box, my nice parameter interface disappears and gets substituted with whatever parameter is defined in the Vex code including my new parameter, which alters the behavior of the code the way I'd expect. So how can add a parameter to my VEX code without having to get rid of my custom parameters? Thanks a lot, Nhat
  4. I want to build a dome camera lens shader (like the one in vray). So I looked into the domemaster projection and it's supposedly an azimuthal equidistant projection. I found a formula here to convert from lat/long coordinates to x/y values: http://lazarus.elte.hu/~guszlev/vet/equation/dspostel.htm q = (PI/2) - latitude x = q * sin(longitude) y = q * cos(longitude) Since x and y are given as a lens shader parameter, I'm interested in the latitude and longitude and thus I want to reverse this formula. However I get stuck when I want to solve for latitude or longitude because it always requires the other angle. Any ideas? Thanks a lot! Nhat
  5. Hi! Looking at transformation matrices of IFD files really confuses me. For one they seem to do exactly the opposite of what the camera's transformation parameters in Houdini are indicating, which I think is because Mantra moves the scene and there's no actual camera like in OpenGL. However what's really confusing me is if I have a camera with SRT, ZXY order and transformations rot(45, 30, 0) and trans(10, 5, 0) I get a transformation matrix in the IFD that looks like this: 0.866025396499 0.353553407243 0.353553391789 0 0 0.707106765732 -0.707106796641 0 -0.500000012618 0.612372443928 0.612372417161 0 -8.66025396499 -7.07106790109 6.53176023263e-008 1 Looking at the fourth row, I would expect to see 10 and 5 somewhere, but they don't show up. When I rebuild the same transforms in Nuke I get identical values for each component but for the last row. But the results from the IFD seem illogical to me. I'm really stuck on this, maybe you guys can help. Thanks, Nhat
  6. Hey guys! Just wondering, if I wrote a custom display driver/output image format using the HDK to write to other image files than the standard set, would Mantra automatically support that too or would I need to write a custom one for Mantra too? Thanks, Nhat
  7. IFD API

    Hey guys! Thanks so much for your input! Yes I looked into the mantra commands but couldn't find enough details about the IFD format. I've manually created some IFDs for which I knew the details of the geometry and used that as a starting point. I don't plan to render super complex geometry this way (not even speaking of FX), but rather render additional elements to our CG.
  8. IFD API

    Hi! To write a custom IFD generator I'd like to know if there's a C++ library for generating IFDs? Or at least some better references than within the documentation to get some more details on how to fully describe geometry etc.. Right now writing out IFDs and look inside to see what properties can and need to be defined. Thanks a lot! Nhat
  9. Tried that, but it takes whatever default value is set there. Or do I have to write a short little VEX code to gather the vertex attributes?
  10. Hi thanks for replying! The bind node shows up as an "Add" node called "Bind1" in my mantrasurface node and is in error state. Am I running a too old Houdini version (12.0.543.9)?
  11. Yes this is in a material shader builder SHOP. Where would I find the bind VOP? Didn't show up in the material builder. Thanks for helping Jon!
  12. Hi! I was just wondering how I can access custom point attributes in SHOP? Get Point Attribute gives me strange results and so does PointAttribute. Any ideas? Thanks, Nhat
  13. And how can I create a brickmap with world-space rastering? All my brickmaps get offset. I looked through the docs concerning volume primitives and couldn't find anything about it. Looking at an ascii .geo file, I see a lot of float values for the volume primitive which I'd like to decipher. So if anyone knows more about this, he's more than welcome to post anything Cheers, Nhat
  14. Ok, thank you very much for your replies! I indeed tried the hbrickmap tool first and preferred to avoid it for the purpose of transferring houdini volume data to prman because of the following reasons: 1. Just because of its nature, it is a lossy process (.geo -> point-cloud -> brickmap) for which especially a lot of data get lost at the brickmap generation process 2. I cannot feed the brickmap with custom data that I'd like to add, or I haven't figured out how 3. difficult to control how much detail remains in the brickmap (-maxerror doesn't seem to make a big difference) And for some reason my volume box doesn't look right when converted to brickmap. Very blocky and very low resolution. Has anyone achieved good results with hbrickmap and volumes?? Thanks, Phong