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..::working with large bitmaps (memory issues)::..

You always try to push the boundary of our texture maps and materials when it comes to rendering out close shots of planets; the NASA Blue Marble maps being about the most highly detailed out there, but try getting them into 3ds max in their native format! They are simply too big, so some Photoshop resizing is required...

...but hang on, didn’t we acquire these maps so we could show detail?!

There is a way around it which is a two step approach, namely splitting the map into chunks and then re-tiling it back together in 3ds max. This, believe it or not, is a much safer approach as you can tile up a larger map size using positioned “chunks” of a single texture map that we have chopped up in Photoshop, simply because this way it uses less memory, and 3ds max doesn’t have to try to assign a massive amount for a single map.

Okay, now we need to save out our map to load it into 3ds max. But what image format should you use? Even though JPEG file formats have smaller file sizes, don’t be under the impression that they are in any way better than TGA’s or TIFF’s. In most cases, you really don’t want to use these image formats as textures, firstly for the most obvious reason – saving out a JPEG image results in lossy compression artefacts over the image, or colour amendments, even at the highest setting (whites can go purple etc.).

However the main problem is their memory overhead. Because a JPEG image is compressed, 3ds max has to decompress this image before it can even map it on your Material Editor swatch sample. That can take up a bunch of memory in itself, memory that you would really want to put to better use. A 15,000 pixel-width sized texture map of the earth may load in faster as a JPEG, but at what cost? Materials and particles are very finnicky when it comes to memory; they like to have a solid unfragmented block of memory to work with. It is better to stick with uncompressed image formats and have the scene take longer to load in any external bitmaps that have the entire program run out of memory!

Enlarge Screenshot By careful cropping and positioning (eg halving, then halving again), texture tiles can be output from Photoshop. Note the positions of the maps so they can be arranged in 3ds max.
Enlarge Screenshot Bitmap tiling and offset can be a little confusing at first but, if you have noted down your initial settings for positioning AND drawn a diagram of where these pieces lie, you shouldn’t have a problem repositioning them.

..::quick tip::..

If the texture tile is positioned correctly using the Bitmap map’s offset settings, it should line up exactly with its other pieces using a Composite map to create the full texture.

Initially published: 3D World magazine, Issue 72, Xmas 2005.

Copyright Pete Draper, November 2005. Reproduction without permission prohibited.