Center of Mass

[Benson Shaw]

The Model>Volumetric Properties command offers a center of mass locator. Is there a way to assign different densities to the various materials in a multi material group/object so that the center of mass will be placed appropriately?

-B?

Edited July 24, 2009 by Benson Shaw

[Pat Stanford]

The Volumetric Properties only work on a single object at a time. You could manually type the data for each object into a worksheet and assign densities and calculate the group center of mass from there.

You can also access the data from Vectorscript, so it would be possible to get the center of a group of objects using a script.

Not great solutions but the only ones I can think of today.

[Benson Shaw]

That's what I thought. I was hoping to manipulate the sizes and locations of several objects in the group for visual effect and easily know the CM for each iteration. Wouldn't it be great if the textures or other graphic properties contained the densities of the various materials they represent. One could then see weights when needed and VW would calc the CM directly. I may take a crack at your worksheet suggestion.

Many thanks, Pat

-B

[islandmon]

Resolving the Centroids:

http://en.wikipedia.org/wiki/Centroid

[Benson Shaw]

Thanks for the ref, Islandmon

Side issue here, The CM of a 360? sweep should be on the axis of rotation. Attached is a fresh VW2009 file with a swept poly. Sweep axis is left edge. Volumetric Properties places the CM off axis. Bug? Pilot error? Precision issue?

Anyone else experience this?

CM is offset with sweep segment adjusted to .25?

CM is offset with a locus at the left edge to force the axis location.

-B