Sketchyphysics don't like imbricated tubes
-
Hello,
I've had a problem with Sketchyphysics recently and, even though I spent nearly six hours trying to find a way out of it, nothng has been found.
I want to put one small tube into a bigger one and then make the exterior (bigger) one start to turn thanks to the Motor or Hinge icon but each time I try the tubes start falling apart or even start floating. I tried changing the shape of the tubes (from box to staticmesh) but nothing changes (I just get various bugs).
HELP!!
-
I just did a quick mock up of the tubes as you explained and don't have any problem. The tubes are grouped individually. The inner one set to ignore, the outer tube of course has a motor joint connected.
-
I will try and search back in previous posts but the crux of it is that sketchy physics has a hard time dealing with "voids" which means that tubes need to be modeled by grouping together strips running the length of the pipe (for nice seams use trapezoids) The more "round" you want the pipe the less wide you want the strips. (I typically use circles with 24 sides...48 even better). Make one strip, define it as a convex hull (or rectangle), copy rotate and then group together. Check this youtube link for a quick demo....http://www.youtube.com/watch?v=DL52inWDqKo
-
hadrien_dugas, I figured it out, change the state of the outer tube to no collision, it will work like you want.
I drew two concentric tubes and grouped then individually. I then connected a motor to the outer tube. When I ran the simulation I had the same problem, as you, the outer tube rotated but moved up until the bottom inside surface came in contact with the inner tube, outer surface. So thinking like a logical person, I tried to make a "bearing" on the end opposite the motor, then grouped the bearing with the outer tube, with the inner tube running through it. I then started thinking about what was happening. I tried static state for the outer tube, well of course it didn't move at all. I changed the SP properties shape to sphere, no change.
I found the no collision state and changed the state of the outer tube to no collision voila' it worked. Video to follow (as soon a get time)
Advertisement