Contributor Malo Posted August 13, 2014 Contributor Report Share Posted August 13, 2014 I have a simple question, that digs me a long time. Why is in CG mostly the Y axis the vertical axis and not the Z axis like in CAD or Industrial programms or machines? I know not every CG App follow that axis behavior. Blender have still Z for the vertical axis. Could anybody explain me the benefit about that. Quote Link to comment Share on other sites More sharing options...
Carlosan Posted August 13, 2014 Report Share Posted August 13, 2014 CAD applications have adopted the Z axis up (right handed coordinate system), as sort of a carry over from drawing floor plans, which is a view from above looking down, so that the X & Y axes are on the floor. 1 Quote Link to comment Share on other sites More sharing options...
Contributor Malo Posted August 13, 2014 Author Contributor Report Share Posted August 13, 2014 Yes, this is the comon way for me, at work and my cnc machines. But why did 3d coat or mudbox, or.. use XZ for the floor and Y for up and down? Quote Link to comment Share on other sites More sharing options...
Contributor Tony Nemo Posted August 13, 2014 Contributor Report Share Posted August 13, 2014 Because they all look at a vertical screen instead of a table top blueprint. Monkey see, monkey do. 1 Quote Link to comment Share on other sites More sharing options...
Contributor ajz3d Posted August 13, 2014 Contributor Report Share Posted August 13, 2014 I'll second Tony's and Carlos' replies. Cartesian coordinate system relies on a plane of reference. This for most programs is the front view and therefore you have Y for up and X for horizontal axis while Z is the depth. Some programs, like CAD software, use top view as a reference plane. Probably because their origin dates back to the pen and paper times. And that is why the third axis - Z, goes up - towards your eyes - when you're looking down on a piece of paper. Also, I think it's easier to teach kids the "Y is world's up" system in schools. It's easier to explain to them that if the Y is a vertical axis and X is a horizontal one in a two-dimensional coordinate system, then Z, an additional axis introduced much later on, is the depth. So this might have had an impact on software development decisions too. Just a thought. 1 Quote Link to comment Share on other sites More sharing options...
Contributor Malo Posted August 14, 2014 Author Contributor Report Share Posted August 14, 2014 Thanks for the replys. I work my whole life with Z UP. But since 3d coat, i have to think different. First i was thinking this must have some benefit, but now after your answeres it looks like it is only a matter of how the people see there work. I always work in topview at work, but in CG you mostly work in Front view. And to keep that view from looking from Z axis, it was rotated by 90 degrees, so Y goes UP in that programs. Very interrestiog. Quote Link to comment Share on other sites More sharing options...
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