Path: chuka.playstation.co.uk!news From: Toby Hutton Newsgroups: scee.yaroze.programming.3d_graphics Subject: Re: creation of tmds Date: 01 Jul 1998 12:18:16 +1000 Organization: PlayStation Net Yaroze (SCEE) Lines: 39 Sender: thutton@TECH10 Message-ID: References: <354f8520.24963808@www.netyaroze-europe.com> <35527A2E.72F907B4@home.com> <6n904u$4sn1@scea> <359965bc.370444681@news.scea.sony.com> NNTP-Posting-Host: 203.103.154.235 X-Newsreader: Gnus v5.3/Emacs 19.34 jamin1@psu.edu (Jamin Frederick) writes: > >You also need to keep in mind that the coordinate space is 32 bit, but > >the viewing space is only 16 bit. ie. An object can sit anywhere > >between -2 billion and +2 billion (I assume, haven't tried it) but if > >the object is more than 32k away from the view point, you won't see > >it. > > So if I have a model about 2000.0 wide, will that easily "blink out" > when I get too far away from it, assuming it doesn't get too small to > see? Yeah, probably. But if you go and make your models all 16000 wide then you'll have real trouble. > > > >That's a reason why you shouldn't make your models too big (I saw this > >was a question in your FAQ). > > Yea, thanks for the answer. I'm not sure if what I posted about being > too small is correct, though. Is it true that a model will distort, > or shrink, if it is rotated all the time? Quite possibly, yes. Well, you shouldn't be compounding rotations of an object anyway (1st rule in 3D transformations). If something is spinning in space you should maintain a rotation value for each axis and increment or decrement that - then apply it to the object. You shouldn't rotate an object a small amount, then rotate the new object some more next frame, etc. That's when you compound your round-offs and get distortion. But it's hard to do it the wrong way on the Yaroze as the libraries are designed to be used the right way. If you were making your own runtime TMDs you may be able to do it the wrong way though, I suppose... Also, if you have really small models, like only 5 or 10 units across, then to see them the view point is going to have to be really close and then you get weird skewwy effects, slow down, textures all crappy... -- Toby.