Is bumpmapping really needed?

[guest]

Good day, folks.
Yesterday I was looking at some photos on the "Earth from Space" website, and an old nagging question came back to me.....
Do we really need bumpmapping in Celestia? Unless you're REALLY close to the surface (in Celestia terms), you see the effects of the Earth's features, but not the actual relief itself. All of the screenshots I have seen of Earth, Mars, etc. showing surface features, now seem exaggerated (although beautiful, to be sure) compared to orbital photos.
Thoughts on this? Am I being too picky?
Ron

[Guest]

Interesting point Ron...and one that's been on my mind now and then. I try to avoid using bump maps for some 'objects'. At the moment I have Don Edwards excellent 16k Earth, Fridgers 4k? Red Mars and Jens 8k moon...all without bumpmapping and they look superb.

I will sit on the fence on this one for a while.

Regards...bh (not logged in).

[selden]

For one thing, bumpmapping provides an initial approximation of properly oriented terminator shadows. Surface textures with fixed shading can only have shadows that point in one direction -- which is wrong at least half the time.

Of course, bumpmapping by itself isn't sufficient, but it's a good start.

[granthutchison]

Even though you don't detect relief, it has a very visible effect on illumination. The half moon is only a tenth as bright as the full moon, because we see the cumulative effect of all the tiny (to our eyes) shadows cast across the moon's surface. Bumpmapping isn't an ideal way of reproducing this effect, but it's better than nothing, I think - just a matter of fine tuning a reasonably hi-res bumpmap so that it's less intrusive in the middle of the illuminated disc, but still has an effect at the margins.
Lo-res bumpmaps are completely unrealistic, I'd agree.

Grant