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About mattjakob

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    Matt Jakob
  1. Spray paint non intersection

    oh that's cool... Ill play with it! Is there an easy way to control the size/density of the spheres ? Is that what you did (setting the density) with spraypaint (dont have houdini right now to test it) ? Thanks!!
  2. The title says it all... I would like to scatter some spheres (with different sizes) like I can do with the Spray Paint tool but making sure they do not interest... is there an easy way to do this ? In the image you can see what I did with the spray paint tool (+ a boolean cut)... the distribution and size is exactly how I wanted it, just I wish they didnt intersect! Thanks!
  3. Hello, I would like to have some objects bouncing around inside a sphere. Is it possible to have the sphere geometry transparent but still act as RBD collider ? thanks!
  4. Hey guys, Im playing with the Wire solver and I managed to get a series of wires from one plane to another to dangle (mostly using the shelf tools). What I would like to do is to start with just a couple of wires and over time increase the number. As you can see in my scene file the number of wires is determined by the scatter nodes... but if I animate the points count there the simulation breaks. Any idea ? thanks! mj_wires.hip
  5. Anyone keen in sharing their setup for vector / 2D rendering ? I'm looking for some options similar to Rhino on how to render more technical drawings (wireframes. solid shading, ...) Thanks!
  6. yup that works... but REAAALLY ??!!? I'd love to know why attribs (nor it's local var equivalent) don't work in the transform node... it's really frustrating
  7. uhm... Im trying to avoid using copy stamp as suggested in H16 and use a For Each loop instead... but I cant seem to make sense out of it! (I watched a few videos and checked the help - but they seem pretty useless / over-complicated). I simply want to copy some geometry (eg. circles) onto some points (eg. on a line) + each point has an attribute --> I scale each geometry based on the point attribute. Seems like a perfect iterative loop over points task! When I put my copy to point(s) node inside the for each loop everything works fine (the copy node only receives one point which is fed iteratively from the the for loop). HOWEVER when I apply the transform node and I use vex (@attribute_name) to try to access the attribute value associated to that point to scale my geometry it doesnt work (I get 0). If I try to access the same attribute using a wrangle node it works. Maybe Im doing something silly wrong with the transform node... but what I do seems intuitively right (type the vex attrib name in the scale Thanks!
  8. That's a great tutorial... I also saw the other one by Rohan (see below). THAT'S A REALLY ABSURD WAY TO PASS COLOUR... can't believe it Octane didnt think of something more flexible and logical..... )
  9. I almost never rendered with Houdini but thought of giving it a try... Essentially I created an Octane material and applied it to my geometry but I want the diffuse colour of the shader to be the colour of my points geometry (and not the colour selected in the shader node). Im assuming it's a pretty basic thing but couldnt find a way to do it (played with material override etc.) ... maybe Mantra gets it automatically (seems a sensible thing) but not Octane. In layman's terms I coloured a series of geometries using some gradients and random values (my points have @Cd attributes). Then I created a standard Glossy Octane material. I want my objects to have the properties of the Octane shader (reflection, roughness, opacity, ...) but use the @Cd attributes in the geometry to drive the diffuse colour. Thanks!
  10. thanks guys! in the end I attached the original straight line as a second input to the sweep and selected 'aim at reference points'. @LaidlawFX if I set the up vector to be 0,1,0 then the skeleton instances dont rotate properly along the spline (I think it's called banking ?)
  11. Hello, I was wondering if it's possible to create velocity vectors from an animated sequence (texture). Ideally something similar to Optical Flow. I can extract movement from geometry (eg. use trail to generate v vector of animated VOP) and I can do basic image analysis (eg. convolution kernel operations on coloured points using VOP) so I feel it could be kind of possible to do it but can't get my head around it. In terms of results I'd like to create a particle system that reacts to an animated texture (eg. overlay particles on a animated texture and have them follow the movements in the video) thanks!
  12. Im trying to sweep a geometry around a spiral I created in VEX but Im having a problem as the cross section slowly rotates. I tried to set @up and @N attributes and use Transform Using Attributes but it generates other problems. As you can see the rectangle that Im sweeping rotates over time (I think it does a 360 rotation over the whole path) mj_spiral_test.hip
  13. Kernel (convolution matrix)

    Hello, I am trying to do some edge detection using a kernel. I need to do this using standard SOPs/VOPs. http://setosa.io/ev/image-kernels/ I saw a tutorial from Entagma (https://vimeo.com/169437381) that basically does the operation by hand splitting out the vectors and multiplying them but it's quite tedious and you dont really know what vectors you're multiplying (QUESTION: is there an order in which pcfind returns the array of points eg. clockwise closest to furthest ?) Is there a better way (using actual matrices / knowing exactly which points) ? thanks!
  14. Round pieces / polygons

    Hello, I am trying to smooth the edges of a fractured (voronoi) sphere... but with little success. Tried the various smooth, subdivide etc. but to no avail. The closest was to add an extrude and bevel but the result was less than ideal. This is my geometry right now. and this is roughly the kind of curvature Im looking to achieve: Thanks!