Transformation Matrix Of Oriented Bounding Box

[3dbeing]

So I bring in a piece of geo through a file node, I then append a box sop, and check oriented bounding box... How can I get the rotations that created this box?

Thanks,

-3db

[sibarrick]

You can build an orientation matrix using an axis built from one of the faces. This could be done in vex.

This thread might help

Orientation of a triangle

Not sure if there is an easier way.

I did write a vex sop to build an oriented bounding box, its up on exchange, that may be useful too.

[antoinedurr]

You can build an orientation matrix using an axis built from one of the faces. This could be done in vex.

This thread might help

Orientation of a triangle

Not sure if there is an easier way.

I did write a vex sop to build an oriented bounding box, its up on exchange, that may be useful too.

One of the problems you'll hit is that the oriented bounding box doesn't really know if your object coming in is right side up or upside down. So it will not constraing the bounding box consistently as the object rotates through space. Furthermore, the face ordering will change on you mid-stream, so building a matrix therefrom will present you with a lot of flipping.

[sibarrick]

Be aware too that oriented bounding boxes give mixed results, the box orientation you get is not always what you would get if you were to position the thing by hand.

Mine works best when there is alot of difference between the scales of the object in all 3 axis.

See attached for a comparison to the box sop.

Also, always wondered why that option is in the box sop but not the bounds sop....

ExampleOrientedBounding.hipnc

[TheUsualAlex]

Hey Simon, that's really cool! It's the first time I've seen someone used eigenvalue/eigenvector (only heard about it in the past, couldn't get it into my head) Definitely worth the study! Thanks man!