CenterOfRotation vs FocalPoint about vtk-js

[martinken]

Have you tried translating the focal point using shift left mouse? That may do what you are shooting for.

[jourdain]

Actually, the issue that we are facing is that in ParaView, when you zoom, we basically move forward the focalPoint and cameraPosition while the centerOfRotation (a property on the view) remain the same.

So when exporting a scene from ParaView, we keep the same focal point which end up being the center of rotation in VTK.js which will mess up any initial interaction. In fact, we would like to keep the same center of rotation as ParaView. So we were thinking that if we could specify it along with the focal point that could solve the problem. Specially if we change the center of rotation on purpose in ParaView to be off-center.

[martinken]

OK, maybe better discussed offline as I'm not sure why PV is doing it the way it is :-)

[jourdain]

Sure sounds good. But the idea is that the Focal Point should not necessary be the center of rotation.

[martinken]

Why are you moving the focal point on a dolly in PV? Why not just the position?

[jourdain]

I agree for that part, that should not be the case. But if we pick the center of rotation to be somewhere else than the current focal point, we should be able to define that in a vtk-js scene.

[martinken]

Is there any interactor style in VTK that does this?

[jourdain]

I have no idea, but that must be the case, since ParaView is based on VTK.

[martinken]

OK, well, just have to put the same logic in the interactor style in JS, so it should be easy.

[jourdain]

See https://kitware.github.io/vtk-js/examples/Manipulators.html