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ascust / 3DMM-Fitting-Pytorch

A 3DMM fitting framework using Pytorch.
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Why should reverse z and puls camera position? #26

Closed shoutOutYangJie closed 1 year ago

shoutOutYangJie commented 1 year ago

Here is your code

face_shape = torch.matmul(face_shape,reverse_z) + camera_pos I don't know what it really means？

ascust commented 1 year ago

This is used to transform the coordinates of the mesh from the world system to cameras local system.

shoutOutYangJie commented 1 year ago

but why not directly use rotation and translale matrix?

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This is used to transform the coordinates of the mesh from the world system to cameras local system.

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ascust commented 1 year ago

I am not really sure about your question. My understanding is that the rotation and translation matrices are defined in the global coordinates to alter mesh's pose. If you want to project the mesh to the camera (or any camera), you have to transform the coordinates to the camera's local ones and convert 3d points to 2d points to have them on the image plane.