Coordinate system in the viewer?

[tve]

I'm a bit confused about the intent of the coordinate system in the viewer. As far as I can tell, the API uses a coordinate system with Y pointing "up" and Z pointing into the scene (typ for computer graphics) but the viewer places objects onto the XY plane and so Z ends up pointing "up", at least the way I see it... This becomes very confusing when one uses the width, depth height accessors.
What is the thinking here? (I realize 3D printers generally print onto the XY plane.) Any chance one could toggle the visualizer between the two modes? Or am I completely missing something?

[sgenoud]

the API uses a coordinate system with Y pointing "up" and Z pointing into the scene (typ for computer graphics)

What suggests this for you? I have worked with Z is up all the time and iterated on the API that way?

[raydeleu]

For me the current definition is fine (or stronger: preferable) as it conforms to the definition in most CAD and 3D tools (for example Blender) where x,y defines the horizontal plane and z defines the height. As mentioned, it is also the definition for 3D printers.

[tve]

I agree with Z being up being preferable. The reason I assumed that the API uses Y-up, Z-forward is the following:

  const box = r.makeBaseBox(10, 20, 30)
  const bb = box.boundingBox
  console.log(`width=${bb.width} depth=${bb.depth} height=${bb.height}`)

which prints:

width=10.0000002 depth=30.000000200000002 height=20.0000002

which is exactly what a std computer graphics Y-up coordinate system would call things...

[raydeleu]

I understand your confusion, I never had the need to assess the bounding box. In the Workbench it looks completely as expected. The names "width, depth and height" are indeed confusing.

[sgenoud]

Thanks, perhaps a little bit of background on why I call these dimensions like that.

I really started drawing with code for 2D stuff - and I used as a convention width and height for X and Y axes respectively. I guess this is not unexpected (is it?, English is not my first language).

The next step is when I went into 3D I needed a new term for the Z axis - so it became depth. I use it as a convention for myself and forgot this is my own convention.

I should probably call the xLength, yLength and zLength to make it more explicit.