Collider Question
Posted: 28 November 2019 06:58 AM   [ Ignore ]  
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This is another simple one: I created a perforated column using the Boole function, and gave it a collider tag. I then set up a paddle rig to spin inside it, also with a collider tag. Then I arranged to feed cloned spheres (rigid bodies) into the column with the expectation that the paddle blades would knock the spheres out through the perforations. But the column seems to retain the “memory” of the original solid primitive, so the simulation ignores the perforations and all the clones spill out the bottom.

I’ve had this happen on similar setups before, and set the relevant shapes to “static mesh” or “moving mesh” to fix it. But that doesn’t seem to work this time.

The odd thing is that one lonely clone makes it out early in the operation - and it seems to have “punched through” whatever force field is holding the rest inside. I’ve seen that before too - as if when the colliding energy is high enough, the simulation breaks down and solid objects aren’t so solid anymore.

I’m sure it’s another one of those confounded click boxes set to the wrong state.

Model attached.

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Funnel Separator.c4d.zip  (File Size: 149KB - Downloads: 2)
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Posted: 28 November 2019 09:48 AM   [ Ignore ]   [ # 1 ]  
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Hi mford610,

I would take the separator out for the initial set up. In this way, you can see how the “Peptides” are kicked in the right direction. The paddles might need an adjustment in size and speed.

If they get thrown in the right direction, place the separator back in.

With this fast-moving and the little holes, you might also explore the “Attribute> Mode> Projects> Dynamic>Expert: Steps per Frame

I’m not convinced that this high Friction value is needed.

The clones can be left on Shape: Automatic

In the separator, I have cheated a little bit, DY-Tag> Size Increasement set to negative.

Example:
https://www.amazon.com/clouddrive/share/5g1ie7hig7EdhtPgeKn2B1SuijTom5ExdVlAZIhFvGp

Happy Thanksgiving.

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Posted: 29 November 2019 09:12 AM   [ Ignore ]   [ # 2 ]  
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Excellent! I don’t exactly understand why it suddenly works better, but it does. Thank you! I redesigned the paddle and that made a huge difference. The physics is real, so it makes sense that the paddle design would be critical. I have new respect for the dynamics engine!

Question: Your model has perhaps 4x the number of peptide clones as the original, yet it previews probably twice as fast. Did you change something that would affect the preview render speed? Whatever it was, I want to be able to do it on the upcoming iterations. I just don’t know what it is.

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Posted: 29 November 2019 09:18 AM   [ Ignore ]   [ # 3 ]  
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You’re very welcome, mford610, thanks for the reply.

I changed many things, but I believe that the Peptide Shape set to Automatic (or Ellipsoid) has sped up the preview. (It was set to Moving Mesh, the slowest)

All the best

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Dr. Sassi V. Sassmannshausen Ph.D.
Cinema 4D Mentor since 2004

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Posted: 29 November 2019 10:50 AM   [ Ignore ]   [ # 4 ]  
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Egads! You are right about using automatic vs. moving mesh. Huge difference - almost real time.

Thank you!

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Posted: 29 November 2019 10:58 AM   [ Ignore ]   [ # 5 ]  
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Yes, mford610, nice that it works for your project.

The difference between all these modes is that they either have a parametrically description of the shape (simplified hull) or take the current geometry into account. Whereby Static- and Moving-Mesh are the two that uses the geometry as shape. These two are the most time-consuming methods. If needed, they can’t be replaced with just a number based simplified hull of the object.

More about this:
https://help.maxon.net/us/index.html#DYNRIGIDBODYTAG-RIGID_BODY_GROUP_COLLISION

However, at the moment things are cached, those advantages in time (or disadvantages) are no longer given.

All the best

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Dr. Sassi V. Sassmannshausen Ph.D.
Cinema 4D Mentor since 2004

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