Working with Textures
From NMC-Campus
A tip 'o the hat to Eloise Pasteur, who posted this to the SLED list 4/16/2008:
Please, please make your signs as small as humanly possible. The issue with big textures is lag at all levels. When you see a texture the sim tells your client to download it, the bigger the texture the more time and bandwidth this takes. In addition, your computer has to draw it - and a 1024 X 1024 texture with no alpha chews up 3MB of your graphics card to draw, a 512 X 512 texture chews up 1/4 of that. How much that affects your machine varies, but remember there are people with 64MB graphics cards out there: do your sign really need to take up 5% of what they can draw?
Also remember that signs do not need to be square. Ideally the sides need to be a power of 2 (32, 64, 128, 256, 512 or 1024 pixels) but not square... 32 X 256 with a 24pt font works nicely to give you a long thin sign for example. If you don't make powers of 2 pixels on each side, the upload interface will automatically resize to do this, and whilst it's not bad, it's not as nice as you get in something like photoshop, where you can see the picture after resizing.
As a general rule, fonts much smaller than 20 pt should be avoided - a bit like they are in powerpoint, but remember you are aiming for the same sort of display interface with an almost certainly much busier graphical environment than most powerpoint presentations. The issue with a lot of signs in SL is that people write too much on them and use a tiny font to try and cram more writing in. You want to make your signs easy to read. You can, in fact, write in powerpoint and then choose export as jpg and get a jpg per slide if you don't have access to a decent graphics programme. You won't get decent sizes of image, but the distortion in text-only displays isn't too bad. You can correct for the distortion (but not entirely for artefacts) by putting the texture onto a sign that is in the same ratio as the original exported file. Say it's exported as a 720 X 540 px texture. This will upload as 512 X 512, but if you display it on a prim that is 7.4m X 5.4m (or some smaller sizes in the same ratio) you will smooth the distortions to the text back out as you stretch the texture back to its original aspect ratio.
The idea of combining multiple signs on one texture saves a little bit on upload fees. It will also make sure that all the of signs load at the same time. This sort of texture sheeting does have its place - but by and large you only want to use it when you know all the signs will be seen by all, or almost all, of the people using the area at the same time. One of the places you see it used sensibly is in furniture building, where you will see all of the textures on the furniture at once from most angles. If people are in places where you use the 1 in 4 texture sheeting described by Jeff, but they routinely only see one sign, then you're wasting 3/4 of the space you're taking up in their graphics card.
