View Full Version : Subdivision memory usage

08-07-2006, 01:49 PM
While playing with a subdivided surface, I found that I was getting out of memory problems. I've since upgraded the machine with 4x the memory, but I'm still getting these - even though the total usage is well below that of the total (now 2G, WinXP).

So I've been doing some tests with subdivisions.

With 1 flat box subdivided in Modeler into 10x10 squares (121 points, 100 polys), I can get to 85 subdivisions (subdivisions per poly) before I "run out of memory". At that point, LW is reporting 205.3M used, and WinXP is reporting a total 625M (for all processes). At this point, I have 724,322 points, and 1,465,000 polys.

I clone the object, and with 2 of these, I can only get to 72 subdivisions, but 294.6M/787M used, and 1,039,924 points, 2,073,600 polys.

With 3, I can get to 65 subdivisions, but 360.1M/906M and 1,271,766 points, 2,535,000 polys.

With 4, I can get to 60 subdivisions, but 409.1M/994M and 1,445,288 points, 2,880,000 polys.

I can't work out any correlation here at all (the point/poly count looks fine, but I just want to know when I should run out of memory).

The most polys I've got is 4,870,520 (I didn't make a note of how I did it, nor how many points I have - ISTR I was playing with two objects, one of which was set pixels per poly, and the other to divisions per poly). At that point, I had 691.7M/1.48G used.

Has anyone else seen this behaviour at all? Or have any explanation? I'm a little stumped by this...

[edited to correct a typo in one of the numbers]