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disappearing bodies and concave confusion

January 27, 2014 | 11:23 am

specs ::: os 10.8.5
NVIDIA GeForce GT 330M 256 MB
max 6.1.3

i’m learning how to use the physics engine properly, and i’ve run into a problem when trying to use concave bounding bodies to jit.phys.multiple particle-like systems.

i’ve been referencing these helpful examples

and the patch i’m attempting is a combination of #5 and #7. i’m trying to create a spherical boundary around a jit.phys.ghost object that can push and pull particles in from and out to the boundary. simple enough i think. however, in my patch, the boundary only works when the jit.phys.body’s shape is dynamic mesh ( whereas, in Cory’s example it also works when the shape is concave ). additionally, even when the boundary works, the particles from jit.phys.mult roll along it only so long before they disappear entirely.

i apologize in advance for any redundancy, i only found one
( ) and i wasn’t able to fix my patch based on it.

the patch is attached. please and thank you ( for your help ) !

Attachments:
  1. 3dphys_7.maxpat

January 27, 2014 | 11:30 am

not sure why, but the hyperlinks i tried to include failed to appear in the post.

i was referencing the examples from the physics patch-a-day at the URL http://cycling74.com/2012/09/19/00-physics-patch-a-day/

and the other similar problem is this forum topic on "strange issues with bodies and collisions" at the URL http://cycling74.com/forums/topic/stange-issues-with-positions-of-bodies-and-collisions/

please note that part of my patch is literally copied from example 5 from patch-a-day. i don’t take credit for it. i’m just trying to emulate it until i can get it to work for learning’s sake.


January 27, 2014 | 11:31 am

so, don’t use the link button, and then your hyperlinks will work? sorry, i’m so new to the forum…


February 3, 2014 | 1:28 pm

concave shapes can be problematic, if the provided mesh is not uniform and evenly distributed. that being said, your patch works fine for me, so i’m not sure what your question is.
if you’re having troubles, try updating to the latest version of max 6.


February 4, 2014 | 10:48 am

sorry if i was unclear.

my question is: why do the spheres from jit.phys.multiple disappear when pushed against the concave boundary by jit.phys.ghost?

it’s still a problem i’m having even though i just updated to 6.1.6.


February 4, 2014 | 10:55 am

also, when i switch to concave and then back to dynamicmesh for jit.phys.body, it no long collides with the spheres


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