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Autodesk Multimedia Forum · Software Dev. Kits

#Z-up

14 messages in this thread

#137566From: WillNov 22, 1994 11:08 PM

I'm writing a ray-tracer and am importing objects from 3D-Studio for the geometry using .ASC files. The Y and Z coordinates are switched when loaded into my program so the objects are sideways. I switched the Y and Z in the 3ds.set file but it didn't change anything. I have fixed this but was just curious, in the reference manual I got the impression it was a Y-up enviroment, (pg. 6-5 ver.3)?

#137613From: Yost GroupNov 23, 1994 9:51 AM

The internal code was written with Z up, but for purposes of documentation (after studying the relationship of the 2D Shaper coordinates to the Lofter) we decided to go with Y up. The 3ds.set file simply lets you switch the labels, depending on your preference. Some people seem to have strong feelings about the two coordinate systems. Generally, CAD systems use Z up, while computer graphics programs use Y up. I'm personally curious. Among those reading this thread, which type of coordinate system do you prefer, Z axis as depth, going in and out of the monitor from the Front view? Or Z axis as height, going up and down from the Front view?

#137666From: CSA/CANov 23, 1994 12:44 PM

Z axis for depth, for me please, hold the onions.

#137677From: MARK A. MEIERNov 23, 1994 1:22 PM

Its "Z axis as height, going up and down from the Front view." for me. Same as AutoCAD. However it really doesn't matter that much because what I always pay attention to is how it looks in the viewports, not how they are labelled. Mark

#137700From: David J. MarksNov 23, 1994 3:58 PM

>> Among those reading this thread, which type of coordinate system do you >> prefer… I prefer the "right-hand" rule where X and Y represent width and depth, and Z represents the height. (Is that the standard notation for transformation matrices?)

#137714From: Brandon MacDougallNov 23, 1994 5:28 PM

I still think in the "z" up. But I have learned to suppress the desire.

#137740From: WillNov 23, 1994 7:54 PM

Am I the only one that likes Y-up?

#137796From: Ted BoardmanNov 24, 1994 6:01 AM

. . Yes<g> !^NavFont01F0006MGHHGQ3DE3

#137875From: ROBERT RITGERNov 25, 1994 11:53 AM

Gary: 'Z' up for me please. Bob

#137881From: JAVIER REYES MORENONov 25, 1994 1:25 PM

– Amazing discussion! . We propose the creation of "THE Z FORUM".

#138332From: New Riders PublishingNov 28, 1994 1:34 PM

Z for me too!

#138243From: SyndesisNov 28, 1994 10:33 AM

You'll find that even among various computer graphics books, they'll choose different orientations for the axes. Somewhere in my notebooks, I have a crib sheet that documents which orientation is used in which book and in which 3D program. It can be seriously confusing if you try to use more than one 3D book at a time while writing code. The implications of the axes choice defined on page 3 of the book percolates all the way through to page 375. 🙂

#138313From: Russ Wood [Insight]Nov 28, 1994 12:45 PM

Jack, <<Z axis as depth>> Please! Russ Insight Development

#138242From: SyndesisNov 28, 1994 10:33 AM

Changing something in the 3DS.SET file doesn't change the organization of the data in the .3DS file – otherwise people wouldn't be able to easily share models.