Topic awaiting preservation: image realism

There is something distinctive about even some the best 3D imagery that stands out as unreal. It's really hard to put your finger on.

Some objects that are especially problematic are those that are supposed to look new and clean. Quite often, when we are simply trying to put together a cool looking image, we add a bunch of dirt, grime, scratches and rust. Some of us have gotten quite good at it. But, I quite often feel that it's cheating.

As an exercise, and a sneaky way to get help on my image .What does everyone think about this image? I'm not really interested in comments on the background (I through it together pretty quickly), but what is it about the car itself that stands out as unreal?
http://www.worldomination.com/porsche/porsche.jpg



edit-- fixed yer italics...

[This message has been edited by Petskull (edited 11-24-2001).]

Well.. I'll start with the model itself.
For starters, you might want to add doors, if this particular car doesn't have doors, then the side still wouldn't be perfectally flat, there would be some sort of shape to it. Next, the chrome and general texture of the car is was to perfect and clear. The tires need attention too, the treads are way to flat. Also, the car looks stretched, both lengthwise, and somewhat curved (this is because of the turned wheel combine with the incredibly smooth texture on both the chrome, and the material on the car).

Now for the materials. Many things in this image are way to smooth, and way to clean. This is most noticable in the reflections, they need small distortions especially the chromed rims on the tires - theres no way the chrome would be that clean, especially after the car has been driving. Also, not all light reflected is white (also, sometimes it just lightens the surface, making bright spots), and its almost never in perfect circles, or ovals, enless you're dealing with a polar ellipsoid, or a sphere. The material on the treads of the tires needs more bump, and should probably be a darker shade - it looks like you have a light shining just above the tire, and not effecting anything else. Most of the reflections on the car look nice (asides from lack of grunge), but the leaves that are reflecting, are reflecting WAY to strongly. The yellow lights on the front of the car are the wrong material, they should be more translucent, and should have a texture and a patern. They should probably also be more orange? Finally, the material on the road looks blurred, and stretched. You need a larger image map, or an image map with higer resolution.

Now, how you can fix it. All I really have to say is, if you haven't yet, check out all of the tutorials at DVGarage.com These are all great tutorials, and almost all of them involve steps showing how to break up materials that are too smooth and perfect. This whole site is actually dedicated to the very things you were tlaking about - taking good images, and making them more realistic.

you might want to check out Bill Flemming's books on photorealism [he's got two now]. It's pretty damn good if you wanna make stuff look convincing. i don't think adding grime and dirt to things is cheating really, i mean its how things actually are in real life. where i live i just don't see clean highlights or perfect reflections on anything. hehe maybe thats just england though.

well, dan already said most of it...
too bright, shadow is too smooth, reflection seems a bit "wrong".

what engine where you using? 3dsm? how long did it take you?

[This message has been edited by me (edited 11-19-2001).]

Thanks guys, good info. I used 3DS Max R3.1, and minus modeling, the texturing and setup probably took about 10 hours.

Yup, some good comments overall here. One thing that folks don't do a lot in 3d is simply look at real-life. They want to imitate something that's photoreal then look at books to see how someone else did it instead of checking out the world around them. Observation is the key, then ask questions of "i noticed this on this object in my living room, how can i recreate that?" You mention that it's hard to recreate things that are supposed to be newer because they're clean, but the thing is they're really not. Go look at the floor at Wal-Mart, or pick up a box off the shelf. That floor is actually filthy, it's got scuffs and smears all over it, and that box is probably dented a bit or slightly lop-sided, has fingerprints on it, etc. Nothing's perfect

One good book I'll recommend is 3D Lighting and Rendering by Jeremy Birn, great book on creating photoreal scenes. The Bill Fleming books are pretty good too. Aside from that I'd say to start small. Get a ball that looks photoreal, then something more complex, then try different materials, etc.

Chris


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