Coordinate System

Oct 16, 2007 at 11:27 PM
Did you want to maintain the Z-up coordinate system currently in use in your template, or are you okay with going with a Y-up approach?
Oct 16, 2007 at 11:42 PM
Different engines do it different ways, I'd prefer to keep it so that I don't have to rewrite some components, like the terrain component, and physics. To me, a Z-up system seems natural, as I simply picture the ground coordinates in x, y.

Take a 2d game where guys run around on the ground, using AI in X, Y coordinates, change it to a 3D game, and the guys still run around in X, Y coordinates, except that we've tacked on the 3rd dimension....Z. That's just how I imagine things. And of course others think the same way and that is why other things are written with a Z-up system, like all of the Riemer's tutorials. I'm ok with either way, although my personal preference is a Z-up, and I would prefer not having to re-write stuff.
Oct 17, 2007 at 1:21 AM
The main problem is with the modeling packing -> game pipeline. If the model is exported with Y-up, the importer will need to account for this.

It shouldn't have any affect on game components, other than the camera classes which define the coordinate system. Physics is unaffected, you just set an appropriate gravity vector. All of the other systems should be coordinate system agnostic. The only component I can see being affected in the quad tree partitioning component, but that's a special case.

Leaving it as Z-up is fine, I just want this decision to be clearly defined so there's no confusion later on.
Oct 17, 2007 at 5:24 AM
The infection game on my site was made with a z-up axis. We simply told the artists to export with that setting. It has never been a problem for me in the past. If I thought it would be I'd go for the Y-up.