Setting the orientation and position of particles for wobble

[Martin Kossmann]

Hi, i would like to know if there is a way to put particles pivots to work best with the wobble operator. This is for a tree rig. Imagine branches coming out of a trunk. I would like to put the branches pivots where they are closest to the trunk looking back at their center or the longest side of the bounding box. To make things more complicated this has to work with the tyswitcher and the tycollect. My setup is utelizing the tyswitcher to load multiple tycollects. In these tycollects are the geo s of the trees. The trees have all the same geo elements like for example 1 trunk and 1 branch object. I voronoi the trunk and element fracture the branches and center their pivots. Before importing the geo into the tycollection i assign a typroperty modifier with an particle group 1 ID to the trunk and particle group 2 ID to the branches. Then i use a birth operator, select the tyswitcher and shuffle out the particles via a property test (particle groups). So i can t use any other birth operators and since i use the switcher and tycollection i can t use any operator that needs a shape input. I d like this setup to be as procedural as possible so i don t need to pick specific geometry in the flow. In my picture example i only use the tycollection to make things more simple.

This sounds a little complicated but i hope my attached images will clarify 

[tyFlow]

Have you looked into the object alignment mode of the rotation operator? Disable 'affect shape' and it'll affect the pivot only. Turn on TM axis display with a Display Data operator to see the result.

[Martin Kossmann]

Have you looked into the object alignment mode of the rotation operator? Disable 'affect shape' and it'll affect the pivot only. Turn on TM axis display with a Display Data operator to see the result.

Hi, yea for sure. But i cant find a suitable way to align this properly. I can t use the shape for example since i have to pick a reference shape. With my setup, i ll rig like 20 trees on the fly in sections with tyswitcher and tycollect. So i can t pick a specific shape as reference. Bounding box kind of works but then some branches axis are flipped and will wobble in different directions. And moving the pivot to the spot where the branches are sitting on the trunk is not solved by this. Any other suggestions?

[tyFlow]

Sorry, I meant the "align to shape mesh (oriented bounds)" mode...I'm used to calling it an OOBB (object-aligned bounding box) since in any other non-particle context that's what it's called. Although yes...if you just feed it a soup of shapes it has no way of knowing what is the "right" way to orient along the longest local axis, so you'll get flipping.

There's really not an easy answer to the question...if you're just feeding it arbitrary triangles, we may intuitively be able to see what the "right" way to align a transform should be, but algorithmically it's a tough puzzle to solve.

[cam.crichton]

excuse the obvious "have you turned it off and on again" comment but if you don't centre the pivots after the fracture does it align them correctly - like can you solve the pivot issue before you input them to tyFlow?