How to calculate a point projected from the local Z axis of camera?

Coding Python Support
1

Long time no post! :slight_smile: Glad to be doing some Python programming in Blender again.

I’d like to figure out how to project a point somewhere down the local Z axis of the camera.

So, say the camera is at 0,0,0, and rotations are set to 90, 0, 0 such that the camera is pointed directly down the +Y axis. It’d be easy enough to project a point an arbitrary distance away down the local Z axis of the camera (let’s say 5 blender units away). The point would have a location of 0, 5, 0.

Now let’s take an arbitrary camera transformation: location of (-1, -2, 2) and rotation of (70, 0, -30). How would I calculate a point 5 blender units away directly down the local Z axis of the camera given these camera transformations?

2

Hi there Oh Snap,


import bpy


cam = bpy.data.objects.get("Camera")
cube = bpy.data.objects.get("Cube")


#local matrix


m = cam.matrix_local
cube.matrix_world = cam.matrix_world


m = m * m.Translation((0,0,5))


cube.matrix_world = m
3

VERY nice, thank you. I’ve always been a little confused by this matrix visualization in the viewport. How do you get rid of the matrix visualization after querying it like this?

4

Never mind.

del(m)

seems to do the trick.