Operating system: Ubuntu 19.04
Graphics card: AMD Radeon RX580
Broken: (2.81 release compiled from source)
Short description of error
Even with even distribution enabled, 1 particle per face and a low count of particles to spawn, the particle system put two particles on the same face but with different sizes.
Exact steps for others to reproduce the error
- Create a cylinder with 32 vertices.
- Create a small (scale 0.05) cylinder to use as a reder for particle.
- Delete the top and bottom faces of the small cylinder so it becomes like an empty tube.
- Enable particle system hair on first cylinder and, choose 30 as number, 1 per face source and disable random order, select as render object the small cylinder, the scale 1.0 and choose to randomize the scale a few (0.5 is ok).
- Play with the number of particles and the seed and more than sometimes you will notice two or more small cylinders rendered on the same place overlaping (specially on the top and bottom faces).
What I expect:
If you count the number of faces of the cylinder (added with default parameters) it will have near 30. If I choose "even distribution" of particles and "1 for each face" without random, what I expect is that all the faces of the cylinder have at least 1 particle, no more, no less.
If there are 30 faces and if I limit the number of particles to exactly 30, there must be exactly one particle for each face.
What happens actualy is that there are 4 particles lying around on the top and bottom faces and I don't know why. And there are no particles on some other faces. And sometimes two spawns on the same place on the bottom or top face of the cylinder.
With complex meshes it makes a mess, specially if I need to paint the weight to affect density. In that case there are more particles on some places and there are no particles on places with a high value of weight.