MS Physics 0.0.9

RicardoMosci

In MS Physics, is it possible to maintain and object inside a rotating cylinder? If I make the cylinder a static mesh it will not rotate. If I don't make the cylinder a static mesh, the object will go through the walls. Please see attached SU 2015 animation.

Attachment

Anton_S

Hello, Richardo Mosci,

To fix this, you have to divide the concave cylinder group into sub convex groups, so that the hollow cylinder is made up of additional internal groups. This can be done with Convexify plugin, by fredo6, which automatically divides solid concave shapes into convex groups. Then the top level shape must be set to compound.

For your model, before using convexity, first divide the outer, hollow cylinder and the inner mixer into separate, internal groups. Then, set the outer cylinder's state to Ignore. You won't need it part of simulation because the green cells will serve as the collision instead. Then ensure that the mixer part is solid (has a valid volume) and doesn't have any invalid geometry. You can use TT Solid Inspector and TT Cleanup for that. Ensuring that the mixer is solid, will yield the proper generation of convex sub-groups when you use the Convexify.

The fixed versions of your model is attached below. You can also try fixing it yourself, by following the instructions above, so that you know how it's done. Also, next time, use components for the green cells to reduce file size.

Regards,
Anton

TREFOIL.skp

RicardoMosci

Thank you Anton. Great help.

Can I slope the hollow cylinder along its axis so that the ball slides down as it moves sideways?

pilou

@Ricardo with your own model
Seems you have not put the motor as it must to be !

I just kill Motor
Explode all one time
Group all except ball
Put the motor
& voilà

Try this one!

cylinderok_ms.skp

pilou

Kill the motor
Slope the Cylinder
Put the motor perpendicular to the cylinder

But of course the ball will be down outside in few moment!

RicardoMosci

Thank you Anton and Pilou.

Can you tell me, step by step how to make the cylinder and the mixer "solid". The box is still going through the walls.

I eliminated the green mesh to make the cylinder simpler.

Ricardo

MIXER.skp

Anton_S

Well, since you removed the cells, that initially served as a collision, you will have to apply Convexify to the outer, hollow cylinder. When you do so, ensure that convexified parts are inside the group where the convexified mixer is and that they are not ignored. You can check out the videos at Convexify's homepage for instructions on how to use it.