The z-axis and camera?

[Leedehai]

Hi - thanks for making this powerful package! Since CeTZ supports XYZ coordinates, I'm wondering, by default,

• where does the z-axis point,
• what the camera model is, and
• what the camera position and angle is? (the lookAt matrix)

From the plots in the manual it appears the z-axis points inward the page & away from the reader, the camera uses orthographic projection, and the camera points from a point in (x>0,y>0,z>0) (but where, exactly?) to (0,0,0).

By the way, it'd be wonderful if this could be mentioned somewhere in the doc

Thanks😊

[johannes-wolf]

3D support is not really there as of now.

The default transformation just sets up z to be (x=.5, y=-.5) (which is a bit random...) (see canvas.typ line ~49) -- it set's up a z-shear matrix. So positive z points to positive x and negative y, which by default is to the top-right or "away" from the "camera". I guess TikZ does something very similar when setting z=....

The 0.2.0 marks branch (+ path decorations) uses a z-up and xy-up vector style key to know where the up-vector should be. There are currently no functions to set up a projection matrix or any kind of "camera", although I would like to add that.