Bump

I've read what I could find in the forums and wiki about "bump mapping" as it's called in SL. It seems to me that, if we're prebumping the graphics, and uploading them with single channels, that the Bumpiness Draw Distance in Preferences is essentially useless.

Does that only apply to AVs which are, apparently properly bump mapped? If so, does it make a difference whether my AV Rendering is set to Normal or Bump Mapped?

Bump map just adds silly wrinkles to your clothes. It's useless. I want to see clothes as the original designer created them. Actually the whole bump mapping feature is kinda useless.

Even though the bump maps are stored locally on your machine, bumpiness draw distance is not useless. The more bumped surfaces you can see, the slower SL will run. Turning the bump draw distance down will help your viewer run faster. I keep mine at 30M. I find that to be a pretty good balance of viewability/speed for my system.

But do we have bumped surfaces on anything other than AVs? Or is this the distance at which a fuzzy representation resolves into actual prim faces? There is no way to apply an actual bump map to a texture on a prim is there? Have I totally missed that?

Thanks for the replies so far, but I'm still a little confused about all this.

On the texture tab, there is a pulldown menu for bumpiness. You can't apply your own map, which sucks, but there are a number of presets like bricks, cut stone, concrete, etc. The lightness and darkeness bumps can be quite useful if you make your texture right. To see the bumps, you need to have shiny turned on. For some reason, bump and shine are on the same graphics setting.

Brilliant. Thank you Chosen. Perhaps 2.0 will allow us to add a custom bump mapped channel to our textures when we upload them, or even apply them to a textured face. It's too bad about shiney. It seems a lot of people don't turn it on. My guess is that shiney is a very broad bump map that applies as lightness. But I'm only guessing.

It also seems that the shiney and bumpy settings have no effect whatever on alpha textures. I suppose that's because the client can only handle one additional channel.

Since we've got a thread on bumpmaps I thought I'd check something I've been meaning to for a while.

Bump maps in SL are all done in Software aren't they?

I think the reason shine doesn't affect alpha textures is because it would require custom specularity maps. Without these, transparent areas would shine, which for pretty much all textures except windows would look all kinds of wrong. Bump wouldn't be a big deal either way since invisible areas would still be invisible, bumps or no bumps, but since shine and bump happen to be inseperable, there we are.

Um, specular maps say how shiny something is for each pixel (i.e. burnished areas of metal will reflect less light than polished areas). It would be possible to use the texture's alpha channel for the shiney as well (as I think you're suggesting for the bump). I'd guess LL probably decided not to give us transparent shineyness/bumpiness for performance issues.

The use of the transparency alpha channel would not be practical as a specularity map for reasons that have nothing to do with performance. Were it solely a perfomrance issue, they could easily have made it a toggleable option, just as they did with all kinds of other settings that affect performance.

The reason not to use the transparency map as a specularity is because doing so would be just plain silly. Every area of high opacity would get high shine and every area of low opacity would get low shine. That would look terrible on most images.

Take a stained glass window for example. On the real thing, the panes that are more transparent aren't any more or less shiny than the ones that are more opaque. All the glass has equal shine, regardless of coloring or transparency level. That wouldn't be possible were the transparency channel used as the specularity channel. Also, the metal framework, the most opaque part of the whole thing, would be problematic as well. For most real stained glass windows, the framework is painted flat black, no shine whatsoever, but under the model of using the transparency alpha as a the specularity map, the opaque framework would be the shiniest part. Obviously that would be way wrong, and that's just one simple example. There are countless thousands more ways in which it wouldn't work. Transparency maps and specularity maps should almost never be the same thing.

Bump.

You're absolutely right, not sure what I was thinking. I guess that's what I get for posting at 3 in the morning.
lol, I was waiting for someone to say that!

No worries. I've done far worse than that when I've posted without sleep.