a cube out of spheres

#1

Hello everybody,

I´ve got a little dynamics problem in Maya. Im trying to build a cube out of spheres.This cube should hit the ground.
The big red spheres should be soft and the grey ones should be hard. The goal I try to archieve is if the cube
hits the ground it should squash.I connected the spheres with bones so they stay as a cube. I put two different ncloth
modifier on the spheres. For the big ones I made the cloth soft like rubber and for the small ones more like concrete.
but everytime I start the simulation strange things happen.
The hard spheres dont stay solid or they breaking through the big spheres. Maybe ncloth is the wrong solution for
this type of animation. Is there a good worklflow to get this done?
Every suggestion is much appreciated!

regards,

Chris

#2

To connect the spheres you need to connect them dynamically with an nConstraint, not with bones.
Here is a scene that does what you describe:
https://www.dropbox.com/s/k113fs278jhnoel/hardSoftSphereCube.ma?dl=0

In this case I created two cloth nodes. The squishy spheres started as cubes with poly smooth(to keep vertex count low), then poly combined then made into nCloth. The final out cloth mesh is then smoothed(3 key). To do the non-squishy ones I poly combined 3 planes such that the vertex positions were where I wanted the black spheres. Then I made that nCloth and set the nClothShape solverDisplay to collision thickness and then set the collision and self collision flags to vertex, and set the thickess to the desired size of the black spheres. (instead one could use nParticles for the spheres, but this was a simple way to create the correct positions)

To constrain the the spheres I selected both cloth objects and created a component to component constraint. Then on the constraint set connectionMethod to Within Max Distance and adjusted the max distance just high enough to create links. (you can use greater distance for more links and stiffness).

With the above you still need to go through hoops if you want to render the black spheres correctly. It is probably simpler just to make them like the squishy cloth but with higher stretch/compression/bend resistance… just keep the base model very low resolution (like a cube with one smooth) then smooth the output cloth mesh to make it look better. The max distance contraint will also make the small spheres very stiff if the max distance is higher than the radius of the small spheres( they will get lots of internal cross links then).

#3

This is exactly what I was trying to do! This is great! I had so many different issues with this I just wanted to give up. Your reply and the scene really helped me out.
Thank you for your help and your brilliant solution . It is much appreciated.

regards,

Chris