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About Behrendt

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    Christian Behrendt
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  1. Intersect All VEX only works sometimes?

    Hi @Aizatulin, thanks for helping again - yes, my original idea was trying to use intersection rays to detect overlapping surfaces. As you can see it also worked fine one most meshes - on others it just wouldn't at all. I now found out about PolyDoctor (a lot of nodes to learn for a newcomer ) - which worked fine for detecting the overlaps. Still I'm interested to find out why my code only worked some of the time. As you proposed I also tried a Y-Offset to fix the problem, which didn't work out. Only thing that seemed to work was setting ttol to "-1" to get any interesections at all, otherwise the intersect didn't seem to hit anything. I guess it's a bias thingy and offsetting the points a little in X/Z would probably help, so the ray isn't hitting a point perfectly. Because when using ttol -1, the number of intersections per point grew, according to how many primitives it was connected to (which makes sense, but was unusable for my purposes). Maybe I will test further in a few days, but for now PolyDoctor worked fine. Thanks again
  2. I think hitting Enter in the Value field works if I tested it correctly just now
  3. Hi everyone, I posted some progress in another thread (Sidewalks - PathDeform? - Modeling - od|forum (odforce.net)). My VEX code for detecting intersecting geometry only seems to work on some parts of the model, whereas on others it does not seem to work at all. My idea for the code was to iterate over all points and fire a ray each up and down, to see if there is more than one intersection (it seems it generates always 1 intersection, for the self intersection), and if the point intersects with the geo, its added to a point group, so it can be fused at a later point. What could be the reason, that it only works on some parts of the model? vector RayDDown = {0,-100,0}; vector RayDUp= {0,100,0}; vector hitPos[]; int hitPrims[]; vector hitUVW[]; float tol = 0.00001; float ttol = 0.00001; int expand = 0; int stepping = 2; expand = expand * stepping; i@IntersectDown = intersect_all(0,@P, RayDDown, hitPos, hitPrims, hitUVW, tol, ttol); if (@IntersectDown > 1) { setpointgroup(0,"Intersecting", @ptnum-expand, 1, "set"); setpointgroup(0,"Intersecting", @ptnum, 1, "set"); setpointgroup(0,"Intersecting", @ptnum+expand, 1, "set"); } i@IntersectUp = intersect_all(0,@P, RayDUp, hitPos, hitPrims, hitUVW, tol, ttol); if (@IntersectUp >1) { setpointgroup(0,"Intersecting", @ptnum-expand, 1, "set"); setpointgroup(0,"Intersecting", @ptnum, 1, "set"); setpointgroup(0,"Intersecting", @ptnum+expand, 1, "set"); } I also included a screenshot illustrating the problem. Thanks in advance!
  4. Sidewalks - PathDeform?

    Thanks @Aizatulin for your input! Your solution is very elegant and provides clean results. I think the only problem for me would be, that the curves I use as input are based on real world data and often can't be smoothed that much without diverging too much from the original data. Also I I'm not dead set on using the PathDeformer at all. My previous experience in modelling is in Cinema4D and I basically just tried to recreate the solution we used previously for this - but of course it has the same underlying problems in Houdini. After sleeping on it for a night I now tried a completely different approach which delivers quite good results so far. I basically take the outline of the curb, sweep it inwards for a small increment (50cm e.g.), then check for intersecting geometry with raycasts, fuse the intersecting points, then taking the new inside edges of the geo, convert it to a new curve, and repeat the process. It yields good results, there are just some stretched UVs here and there, but I think I can live with that! And I think with a bit more tweaking I could even get rid of those somehow. This was a great learning experience, as it's the first time I feel I've used Houdini "properly".
  5. Sidewalks - PathDeform?

    Hi all, I'm new to Houdini, so please forgive me if this has been asked 1000 times before (search function didn't return anything useful - although I might not know what terms I have to search for). I have to generate sidewalks for a city. I've been fiddling around for 2 days now and have aquired a somewhat semiusable result with the Pathdeform node. I'm basically sweeping a prefab curb along the curves of my sidewalk outlines. Now my problem is obvious - blending tangents/using point attributes creates a smooth result, but unrealistic. Without blending I have overlapping polys. Sadly my sidewalks don't conform to a grid, have terraing heights etc, and have all sorts of different shapes, so detecting corner pieces for a modular approach probably also won't be an option. I also tried voxel meshing the overlapped result and ran Instamesh on it, in order to try to attribute transfer the UV coordinates - which worked somewhat, but sadly in the overlapping regions there expectedly are problems. Although my problem is most likely in my general approach and nothing a checkbox or slider will be able to fix, hopefully someone can give me a few pointers Thanks in advance!