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About agelosc

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    Athens, Greece
  1. grain collision accuracy

    Hi all, I have a yarn pop grain setup similar to the entagma tutorial called "Connect The Yarns - With the Pbd solver". In short particles are connected with polylines and constrained through the grain solver between them making them behave like wires. This works nice and well but I can't seem to get accurate collisions on the "wires". I've tried to up the substeps on the popnet node and the min substeps on the popsolver to ridiculus amounts but the particles are still going through my fast moving collision object. I understand fast moving objects need more subseps but I'm not sure I'm increasing the right values. Am I missing any other settings that would increase accuracy to a point that I get no intersections? I've attached a test scene. Thanks in advance. collisions.hipnc
  2. inverskin rotation offset

    Thats actually perfect. Much easier than expected. Thank you.
  3. Hi, I'm trying to create a spine with custom twist control. Naturally I've set up my bones to follow a curve, and I've created my custom twist attributes on the same curve. Each point of the curve coresponds to a bone. Inversekin chop has taken over the rotation of the bones so I'm assuming I need to filter through the channels of the inversekin and add an offset to only the rx channel for example. The offset number will finally need to be queried from the curve points. Can you point me to the direction of how I can go about doing something like this? Or something else entirely if you think I'm approaching this all wrong. Thanks in advance.
  4. parameter value relative offset

    Well, yes exactly. Awesome, thank you.
  5. parameter value relative offset

    Thank you, I was hoping for a parameter interface feature I might have missed but thanks either way.
  6. Hi, Is there a way to set a parameter value to the result of an math operation using the current value. In maya for example, in the channel editor you can set the value to "+=10" or "*=2". This will add 10 or multiple by 2 the current value. This makes sense when multiple objects are selected and you want a common relative offset and not an absolute value or an expression. Thanks in advance
  7. Extracting the rotation this way worked great. Thank you. Here's the vex code in case someone is looking to something similar, note that the intrinsic attribute is a 3x3 matrix with only the rotation and scale, just ignore the last row and column from the examples above. matrix3 m = primintrinsic(0, "transform", @ptnum); // extract scale float s[]; for(int i=0; i<3; i++) { vector r = set( getcomp(m, 0, i), getcomp(m, 1, i), getcomp(m, 2, i) ); s[i] = length( r ); } // extract rotation for(int row=0; row<3; row++) for(int col=0; col<3; col++) { float val = getcomp(m, row, col); setcomp(m, val/s[col], row, col); } float scale = 0.5; matrix3 mm = ident(); scale(mm, set(scale, scale, scale)); mm*=m; setprimintrinsic(0, "transform", @ptnum, mm, "set");
  8. Hi, I needed to scale down the objects of my RBD sim and the way to do this is well covered in an entagma turorial. In short, a geometry wrangle node connected in the pre-solve input of the solver, gets then modifies and then sets the transform matrix of the packed primitives using the primintrinsic functions. I need to control the scale with an animated value but to do so I need to set the absolute value of the scale. The way it is now the transformation is relative. For example if the input value is a constant 0.5, applying this scale to the input matrix modifies the modified matrix and is quickly solved to a scale of 0. What I want is to keep the scale constant at 0.5. I was under the impression that a 3x3 (as well as 4x4) matrix has its scale values diagonal at row 0 column 0, row 1 column 1 and row 2 column 2. If that was the case I could just set these values. However when the object is rotated by the solver it looks like the rotation is solved as a skew/scale combination. Modifiing the values above gives a different result from the expected. Is there a way to extract the rotation from the matrix and then create a new matrix with my absolute scale and appy the rotation only to it? Or is there any other way I can achieve this? I've attached an example scene. absoluteScale.hipnc
  9. RBD size/scale change during simulation

    That's perfect, thank you.
  10. Hi, Is there a way to change the size/scale of the rigid bodies during the simulation? I guess it can be done after the simulation but I'm wondering if this can be achieved during so the collisions are consistent. Thanks
  11. Hi, Is there a way to change the size/scale of the rigid bodies during the simulation? I guess it can be done after the simulation but I'm wondering if this can be achieved during so the collisions are consistent. Thanks
  12. flip interior emitter and velocity

    That's good to know, thank you.
  13. flip interior emitter and velocity

    I thought that Volume Source was sourcing a volume from the Fluid Source node but I think I'm still confused about what an SDF is and how it works. While we're on the subject, I ended up using PointsFromVolume after the isooffset and set the FluidSource method to Stamp Points. I found that this way is simpler if you want to set custom velocities on the points and pass them through the same SourceVolume in DOPs. Hope this helps someone.
  14. flip interior emitter and velocity

    In case someone else is looking for this, I've managed to emit from a volume instead of the surface by using the "Sample Volumes" Method on the Fluid Souce node and using an isooffset in between my geo and fluidsource. I'm still not sure about the reasoning of this but it seems to work.
  15. flip interior emitter and velocity

    Hi all, How can I emit from the interior of an object into a flip object with sop level velocity. The shelf tool "Emit Particle Fluid" creates a Fluid Source SOP and a SourceVolume combo but I can't find if I can set it to emit from the interior instead of just the surface. I know I can create a volume of particles through the intial data tab on the FlipObject node but I want to constantly emit, not just on the first frame and I'm not sure how to inject velocities using this method. Thanks