What is the best way to set the "insertion point" of a mesh?

Questions
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1

I’m looking to understand how best to set the “insertion point” of a mesh in Three JS. (For those familiar with AutoCAD, conceptually I’m trying to set the block insertion point)

e.g. If I create a mesh from extruding a shape and I want the “insertion point” to be at the bottom center of the end result, how do I set this?

If I pretend the above ramp is my mesh… and let’s say it is 8 x 8 on the bottom, and when I design it, the closest corner is actually at 0,0,0 (and farthest corner at 8,8,0) I want to adjust the insertion point moving it over (-4,-4,0) so that the bottom centroid is on 0,0,0.

My intention is that once the mesh has been created (could be hundreds of copies), I want to be able to rotate it around the Z axis… and then place it somewhere in my scene with mesh.set(x, y, z);

(Please note, if there is a better way in general to do this, I’m all ears… e.g. if it is possible to use the bottom left bounding box corner of my meshes as the 0,0,0 point, and set a per-mesh point where rotations should be applied around that would work too.)

2

I assume what you want to do is translating the geometry ? See BufferGeometry.translate in the doc

You can also add you mesh to a parent Object3D, then update the mesh position, so that the parent mesh origin represent the “centroid” that you seek.