I'm Cheap! What's Free?

[dougc]

I was under the assumption that the whole image didn't have to be rendered all at once. -I have no very good books that go into this, however.

[Gare]

Hello Doug--

A "big model", like most phrases, depends upon the context within which the phrase is used. There are oodles of ways you can bring your system to its knees using a modeling app: use a lot of different parts (in which case, the saved file size will probably be a tip-off...like 15MB or such), human hair can be defined and then the rendering engine will take forever, you could also perform reflection tracing to 5 or six redundant reflections and let the rendering engine waste a day or so...I guess the opposite of "big model", at least the way I'd define it is, "economical model", or "thoughtfully executed model".

NOT that grand scenes should be avoided, heck no. It's just that with every generation of processors comes a generation of equally ambitious programmers and we all think our machines at home can outprocess a Cray or a Solaris or something.

On the topic of economical, user friendly modeling/rendering/animation apps, remember Amorphium, the cute product that encourages you to poke at primitives as though they are sculpting clay? Electric image is now giving it away if you buy 3D tools for $299. Attached is an Amorphium image (The product is $117 U.S. currently).


My (opinionated, as always [img]/infopop/emoticons/icon_smile.gif[/img] Best
Gary David Bouton

[Zorganite]

ook, you know, I started using Wings, it's a lot better than what I thought it was, espescially once you learn how to use it more (which I'm still working on.. '^_^)
3DC has some more options, but overall, I found wings to be better (but that's just me...)

-Zorg

[bmh216]

Well, a raytracer works in kind of a strange way: "rays" are emitted from the camera (as opposed to light rays entering a camera in the real world). At least this is how I've come to understand it. There are many good references online concerning this subject. Early raytracers were very slow to render, requiring high computational times (as they still do). Machines have gotten faster and the calculations have been optimized so that raytracing no longer takes hours to render, even on a modest machine.

The image is raytraced. The thing in the back is supposed to be a mirror. Do you see why "backfaces" must be rendered? Do you see how it wouldn't be possible to not consider the whole scene at once? The render engine needs the mesh of the whole scene to complete the tracing. AFAIK, anyway. I hope I'm not explaining this wrong, and as I said, there is much info on raytracers available online.

The image is very simple, and is NOT radiosity, it is fake radiosity using area lights. It took about 3.5 minutes to render on a 400Mhz machine with only 192Mb RAM. Not too bad.

[Gare]

The computational power required to calculate backfaces is enormous. Ed Catmull, who I believe still works at PIXAR, first introduced the Z-buffer to modeling apps as a way to calculate and then dismiss backface rendering, 'cos you don't need those calculations for the final render, anyhow. Today, most modeling apps use a Z-buffer engine to speed processing of the final image.

At least, this is what I read in a book on Maya 4 [img]/infopop/emoticons/icon_smile.gif[/img]


My 2 cents, natch'


Gary David Bouton

[bearsclover]

Hey! Anyone have any recommendations for freebie (or inexpensive) 3D software for the Mac? (OS 9 or OS X)? Thanks!

[gnurf]

Wings 3D is a really great modelling application. And it runs on Windows, Linux AND Mac OS X. Try it out!

-Paul

[dougc]

I'm imagining things I'd want to be able to do...
Two questions:
-What 3D modeling software supports depth of field?
-What modeling programs support lensatic effects (such as fish-eye, etc.)?
I wonder because most 3D rendered mages I can casually recall have unlimited depth of field and use flat-field projection....?

[bmh216]

Doug,
All the major players support depth-of-field (DOF) natively. I personally don't care too much for Lightwave's native DOF, it's very limiting and I like to target the center of focus with a null, so I use X-DOF2 (a very nice plugin for Lightwave). As far as cheap or free apps, I'm not real sure you'll find DOF included, it's not really a low-end effect. I've attached the same scene as above, but with X-DOF set to focus on a null placed at the foreground corner of the yellow box. Notice the effect; it has limited uses, but really calls attention to the item(s) that are in focus.

As far as lens effects, I can't give you a list of apps that support them, but these are really dependent on what controls the app allows for the camera. In Lightwave, you have Lens Focal Length, which works just like the focal length of a regular camera lens. See below a render with the camera set to a focal length of 2mm. Gives you that fish-eye type render. You say that most 3D images use "flat field projection", but this really isn't true. Granted, alot of CG images look "flat" compared to photographs, but all 3D apps that I've worked in can use a perspective view for the render, unless you're looking at an isometric view render such as offered by CAD programs and the like.

Anyway, a couple examples follow, hope this shows you what I'm talking about.

Brett

[bmh216]

Sorry, these are out of order, but you get the idea.