I’d like to know the technical details of the Zbrush coordinate system - is it left or right handed, and which axis is up.

Thanks,

Graeme

I’d like to know the technical details of the Zbrush coordinate system - is it left or right handed, and which axis is up.

Thanks,

Graeme

Zbrush uses standard coordinates as far as I know. Just like a 3d line graph… the Y axis is Vertical, the X axis is horizontal and the Z axis is near and far. Positive to the north, east and towards you… and Negative is south, west, and away from.

Hope this helps,

Michael

Unfortunately, there’s no such thing as a standard coordinate system in 3d.

I’ve used 3d packages that have z as up,

and then there’s the left and right handed differences…

We use renderman which is a left handed system, whereas a lot of modelling packages, especially those which use OpenGL are right handed. Converting between the two is not always as trivial as applying a scale of (1,1,-1) when transformations are involved…

My bad, When I said standard coordinates I was thinking mathematically… you know, like a sine wave graph used in trigonometry.

Even if a 3d app has these coordinates mixed up with z pointing up, they still all go by the same mathematical line graph don’t they? I’m sure that there is a standard involved in XYZ coordinates. World coordinates use the same math as object or polar coordinates it is just that the axii are pointed in different directions. As far as I know XYZ coordinates are standardized, that is what floating point mathematics are about and you can’t do 3d imagery without using floating point mathematics. When you say right handed and left handed that is where I get all confused? Can you clarify? Is this an inverse of the xyz axii?

A left-handed coordinate system is with the positive X-axis pointing right and the positive Z-axis going away from you into the screen. A right-handed coordinate system is with the positive X-axis pointing to the left and the positive Z-axis pointed towards you, away from the screen.

In ZBrush the positive Z-axis is pointed towards the screen (into the canvas, away from the viewer), the positive X-axis is pointed right and the negative Y-axis is pointed up. I think ZBrush might be considered a left-handed coordinate system even though the positive Y-axis is pointed down rather than up. (Think of it as your thumb on either your right or left hand pointing in which direction the positive X-axis is going).

In world coordinates, the top-left corner of the ZBrush canvas would be considered the origin.

Thanks for the clarification Winged one!!!

best regards,

Michael

That would make zbrush right handed I think. Anyone have the definitive answer for me?

You can easily recheck WingedOne’s explanation yourself using the info subpanel in the transform palette.

right handed:

+X move tool UP

+Y move tool PUSH

+Z move tool LEFT