Jump to content

DOP groups for rbd Packed Objects


mrWolf

Recommended Posts

I have a RBD sim, with 1 packed object which contains 9 elements.

I am trying to disable the gravity only on certain elements, within the packed object.

 

In order to achieve this, I would like to control the gravity node with a dop group.

 

I created a point attribute "falling" which I control in a sop solver, within the dop network.

Then I created a DOP Group that creates a group based on the following expression:

 

point($DOPNET+":"+$OBJID+"/Geometry",$OBJ,"falling",0)

 

post-1409-0-62246900-1427424243_thumb.pn

 

Now, this seems to work but ...not quite. 

I see elements that start fluctuating at a certain moment, but this moment doesn't match the moment when the "falling" attribute is triggered to 0.

 

To start, I'd like to understand if I am using the above expression correctly.

 

I am quite confused with the global variables $OBJID , $OBJ used with Packed Objects.

 

Could anyone shed some light on this?

 

I am on H13.0.547

Edited by mrWolf
Link to comment
Share on other sites

Check this thread:

POP forces and Bullet sim

 

hi Pradeep,

thank you for the example hip file, very much appreciated.

Your explanation makes sense and it works great !

 

I was trying to stay in the rbd land and use the old style way to drive rbd objects.

But I guess with rbd packed primitives , since we deal with points and transformation matrices opposed to real geometry, we are suddenly in a pop world instead !

 

I've read often here and there that it's possible to access the real geometry of a rbd packed primitive in a sop solver (meaning, unpack ... use and re-pack), but I wasn't able to accomplish this. Meaning that when I re-pack the element it's not the same as the one I unpacked (primintrinsic are lost when unpacking), so the sim breaks.

Is there a proper way to actually extract the packed data , within DOP, use it, and repack it seamlessly ?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...