Path: chuka.playstation.co.uk!scea!peter_alau@playstation.sony.com From: jamin1@psu.edu (Jamin Frederick) Newsgroups: scee.yaroze.programming.3d_graphics Subject: Re: creation of tmds Date: Tue, 30 Jun 1998 22:29:40 GMT Organization: SCEA News Server Lines: 46 Message-ID: <359965bc.370444681@news.scea.sony.com> References: <354f8520.24963808@www.netyaroze-europe.com> <35527A2E.72F907B4@home.com> <6n904u$4sn1@scea> NNTP-Posting-Host: 204.240.38.127 X-Newsreader: Forte Free Agent 1.11/32.235 On 30 Jun 1998 11:27:27 +1000, Toby Hutton wrote: >jamin1@psu.edu (Jamin Frederick) writes: > >> >> In this code and others I've seen, it looks like the TMD coordinate system is >> the same as RSD coordinate system, i.e., 1000.0 TMD == 1000.0 RSD, etc. Now >> are the TMD coord numbers converted to fixed point (12-bit) when it is given >> to the playstation? I mean, do we have to mess around with fixed point at >> all, or do we just use the system of RSD and TMD (assuming they're the same), >> with vertices usually in the range of +-500.0 to +- 2000.0 or so? B/c there >> are only 3 integer bits for 12-bit fixed point, meaning you can only get at >> most 7.something? > >I was under the impression that fixed-point is used only for the >normals in a TMD file. Vertices are 16 bit ints. > >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? > >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? If the model is big enough, will this not matter?? Jamin >-- >Toby.