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Wikipedia:Featured picture candidates/Bump map vs isosurface3.png

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Voting period is over. Please don't add any new votes. Voting period ends on 13 Jan 2011 at 20:57:26 (UTC)

Original - In 3D computer graphics, bumps, wrinkles and dents on the surface of an object can be simulated by using bump mapping. A bump map changes the way the surface appears to reflect or refract light and can increase the realism of computer-generated images without significantly increasing render times. The technique is limited in that it does not actually modify the shape of the underlying object. On the left, a mathematical function defining a bump map simulates a crumbling surface on a sphere, but the object's outline and shadow remain those of a perfect sphere. On the right, the same function is used to modify the surface of a sphere by generating an isosurface. This actually models a sphere with a bumpy surface with the result that both its outline and its shadow are rendered realistically.
Test 1 example image with a narrower angle of view and high quality render settings turned off
Version 2 improved perspective version with fog and focal blur turned off.
Reason
This is a simple raytraced image illustrating a key (and therefore encyclopaedically valuable) limitation in the 3D-model texturing technique known as bump mapping. See the caption and the very detailed description on the image page itself for more, or have a look at the bump mapping article itself.
One guarded positive comment to an early version was made at Wikipedia:Picture_peer_review/Archives/Oct-Dec_2010#Bump_map_vs_isosurface which I should respond to: there are certainly better examples of raytracing available on Wikipedia (some of them are featured already), but that is not what this image is representing - it is representing a specific technique in raytracing using an arguably compelling "spot the difference" approach. There is nothing else which adequately illustrates this limitation so it is wikipedia's finest from that respect.
Articles in which this image appears
Bump mapping (an older version of the image)
FP category for this image
Wikipedia:Featured pictures/Sciences/Mathematics (since it graphically represents a mathematical modelling technique)
Creator
GDallimore (Talk)
  • Comment. I can't tell what the difference is between the two balls. The caption seems to be discussing a difference but then the images look alike. Also, although I am not a mathematician, I think I should probably be able to understand most technical explanations if an effort is made to make them accessible. But this one baffled me. Consider writing the caption to make it discuss the features of the images (or make the images look more different). And write the caption so that it is not so dependent on out of article link clicking. Maybe it is impossible, but give it a shot. Can you convey the "so what", more clearly?TCO (talk) 09:22, 12 January 2011 (UTC)[reply]
I reread it and understand the concept now. One way has a perfect circle, the other doesn't. Consider making it simpler or quicker to understand though. The other thing is part of the caption discusses "changing the actual surface" in a manner that suggest physical actions. But the whole thing is a model. So this wording could be improved (common issue with modelers).TCO (talk) 09:28, 12 January 2011 (UTC)[reply]
I'm not pushing this, but maybe if you had some red dashed line or the like for the outline, it would help make it clear faster for blockheads like me, what the key point is. Other than that thee bumps look great and so the shadows.TCO (talk) 09:31, 12 January 2011 (UTC)[reply]
  • I agree it's hard to spot some of the key differences in the thumbnail, but I don't agree that it's difficult in the full-size or even preview versions. The differences are always going to be quite subtle, since bump-mapping is a pretty good technique despite its limitations, so I don't think there's any way to really make the differences stand out in the thumb version without really pushing the technique to its limits so that the bump-mapped sphere just looked terrible. I don't think the lines and circles you suggest adding would help. I'll have a final think about the blurb - I tried to be pretty careful about the whole "modelling" thing, but see a couple of places it can be improved, so thanks. GDallimore (Talk) 20:49, 13 January 2011 (UTC)[reply]
  • Friend, just fix the blurb and it is copacetic (and I will support you). I agree the red dashed lines would be bafugly. And yeah, I can easily see "it" when I know what to look for. But weeding through all that spinach about the programs and all makes it hard to get the key aha right away. Look how simply I expressed it when I finally understood it was circle verus non-circle. I would not write a caption like that even in a formal science paper, nor would I do it in Wikipedia (although oddly sometimes Wiki acts more technical than real technical articles). I remember reading something on "how to write science papers" (some book or such) that figure captions are some of the most high value text you have in your entire manuscript, so hone them. I think you can actually keep all the detail, but just say something at the very front to the effect of "Bal on the left has a perfectly circular outline while the one on the right has a bumped outline." (then still include all the stuff about the programs and all in later sentences). But call the reader attention to the key visual aspect of the picture first, rather than making him read through all that stuff, think, look, think, look. Also, I think referring to the surface as if it were an actual physical object is confusing (and wrong, there was a great review paper done on how mathematical modeller's language of discussing things as reality can actually affect their work negatively.) Anyhow. Good luck, man. It's really no big deal, just sharing in case it helps.TCO (talk) 20:59, 13 January 2011 (UTC)[reply]
  • Sorry if my reply came across as suggesting you were being unhelpful. That really wasn't the intention and my "thanks" were meant honestly. And the suggestion to get the main point across early is a great one. GDallimore (Talk) 21:05, 13 January 2011 (UTC)[reply]
  • Weak support I've thought quite a bit about this image the past couple days. I really like the educational value of the image; it definitely adds a huge understanding of the concept to a layman. That said, it's hard for me to fully support the image for FP, as it doesn't seem particularly "eye-catching". I've tried to think of a way to really make the image grab you a bit more, and let the viewer understand the concept without close inspection, but I haven't come up with anything. Great work though. Jujutacular talk 20:21, 13 January 2011 (UTC)[reply]

Not Promoted --Makeemlighter (talk) 20:54, 13 January 2011 (UTC)[reply]