Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!husc6!rutgers!ames!ptsfa!well!ewhac From: ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab) Newsgroups: comp.sys.amiga Subject: Re: Interchange program for Sculpt 3D and Videoscape3D Message-ID: <4413@well.UUCP> Date: Mon, 9-Nov-87 18:44:02 EST Article-I.D.: well.4413 Posted: Mon Nov 9 18:44:02 1987 Date-Received: Thu, 12-Nov-87 06:20:44 EST References: <3557@ccicpg.UUCP> <4382@well.UUCP> <4386@well.UUCP> <4391@well.UUCP> Reply-To: ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab) Organization: Williams Electronics, not the makers of Marketroid. Lines: 174 Summary: Makes a nice change from the CBM wars.... [ Insert CBM 2000 flamage here. ] You know, it's weird. Every time I say that I find VideoScape easier to use than Sculpt, people look at me like I come from another planet. In article <4391@well.UUCP> jfoust@well.UUCP (John Foust) writes: >As for moving objects to get ersatz animation out of Sculpt, I suggest we >both wait for lessons from Ken Offer, the guy who did the Kahnankas and >RotAmiga scenes for the BADGE contest. He uses .scripts exclusively. At >COMDEX, he showed another animation that blows the socks off both of those. >It is a little perpetual motion boing ball factory scene. There's a >unicycle in there, too, someplace. > Good Grief! Three Sculpt animations???!! How do I talk to this guy? >As for Sculpt and points, it will only create a point once. It will only >allow one triangle at a given set of vertices. So when my program converts >coplanar coincident polygons to Sculpt, I put both in the .scene file, but >Sculpt only listens to one. > Oh, good. That's a powerful piece of knowledge that should be (but isn't) in the manual. Or is it? >As for the problems of object size relativism, I came up against that wall, >too. Niether program has a "meter", so all coordinates are relative to >each other. For each scene, you determine the standard unit meter size. Actually, I don't consider this a problem. The animator simply decides how "big" everything is going to be at the outset, and scales everything accordingly. This arbitrary scaling works great for VideoScape (uses floating point), but I don't think works with Sculpt (which I hear uses fixed point). The reason the outside radius on my unicycle wheel is 40 is because that's what size fit best on my piece of graph paper. The only time scale becomes a problem is when someone else wants to use your object in their scene. Then they have to know the size of your object, and re-scale it. (Yes, I know you said this.) >Allen exploits this in the HouseAndYard file. The windows are two surface >details, not one. First a black square, then a blue one. The black square >is rendered, then the blue one, at the same endpoints. *But the blue >window is still surrounded by a black border.* Why? > I'll bet he used the unfilled border option. I'll go stare at the file. >What about the way VideoScape clips polygons? It uses a very crude method. >It first checks the centroid of the polygon. If the centroid is not >visible in the viewing window, then the polygon is not drawn. [ ... ] Now *this* I didn't know. I consider this a bug. I'll talk to Allen about it. >Sculpt is much nicer about this. In its Painting mode, where it renders >objects as shaded, non-ray-traced polygons, it does a complete painter's >algorithm and correctly clips intersecting and overlapping triangles. [ ... ] Yes, I noticed this behavior. Intersecting solids are done right. The behavior of VideoScape's polygon rendering has bit me. The floor in The Dream Comes Alive is composed of some 350 polygons. This is to prevent the software from screwing up the drawing of the unicycle. Allen since told me a neat little trick, which I used in The Dream Goes Berserk. It's inelegant, but it works. >If you want to create complex objects, it is very difficult to create >planar polygons, especially if the object has a subtle shape. Thinking >about 3D slopes is one answer, but it is not an easy technique. > Tell me about it. A couple of planes in the unicycle's seat I happen to know are non-planar. I had no choice but to do it this way, due to lack of a solid modelling package. >This business of specifying the outward normal of the polygon takes a lot >of mental energy, too. [ ... ] Not to mention the fact that, if you get it wrong, things come out looking weird. >Aegis should not have sold VideoScape for $199 without a >user interface for making objects. Agreed. D3D (a/k/a ROT) was not a viable excuse for a modeller. >They have announced an object editor >destined to ship in four or five months, priced at $149. GAAAKK! That's a bit overpriced.... >Meanwhile, I'll >try to sell InterChange to everyone else who owns VideoScape. You've got at least one sale right here. >Some example VideoScape objects list the same point several times. [ ... ] This bugs me, too. The new modeling program will collapse redundant points. The main contributor to this is OCT. EGG is also guilty of it. >How can you hand-check a VideoScape GEO object for problems like >non-planarity? How can anyone examine a GEO file? Or how could you find a >bug in your enumeration of the vertice list? Without a tool to enumerate >the vertices for you, it is impossible with more than a few dozen points. >I have considered writing such a tool. I have in-house routines to do it. > Can I get your tools? Do they come with InterChange? They sound very useful.... >Consider Leo's unicycle. (I have converted it to Sculpt form.) The fork >and seat has 1669 points and roughly 1400 polygons, with some polygons >having as many as 36 vertices. (Most had 4 vertices.) The wheel has 1576. >The whole unicycle becomes 5012 triangles when converted to Sculpt. [ ... ] Big, isn't it? :-) >Isn't this a little overkill for an object that is ultimately rendered with >about twenty pixels across? Come to think of it, isn't this overkill for a >program that only allows eleven colors? [ ... ] Not at all. Unlike Sculpt, we don't have edge smoothing. I wanted a cylinder to look like a cylinder no matter where I was looking at it from. I'm rather proud of the fact that I spent a lot of time on the little details of the cycle. Yes, it takes a long time to render; but I think the results are worth the time. No matter what angle you look at the cycle from, it looks good. By contrast, Allen Hastings took my unicycle, reduced the number of points and polygons in it, and used the result in the Car Demo. I can see the difference. So call me weird. >Did you notice the colors are fully IBM compatible? [ ... ] Yes. I wasn't impressed. Oh well..... >The selection of colors is completely arbitrary, unless >you consider that it may be ported to the IBM. The limitation on the >number of colors is completely unnatural and arguably criminal on the >Amiga. [ ... ] I found the color limitation very strange, too. But Allen has pulled all kinds of trick just so that he doesn't have to wait so long for a frame to be rendered. Which is perfectly within his right, I suppose. >Speaking of ports, Bill Volk has ported the ANIM of "The dream goes >berserk" to the Mac II. > Now that *is* criminal. >Leo, you are quite unusual to be able to write C programs that induce >VideoScape to have motion blur and Newtonian physics. You also have good >directorial skills, as does Allen Hastings. Most people don't. > All right, I'll admit my mind works a bit differently from everyone else's. But do please believe me when I say that, no matter how implausible it may sound, I find VideoScape easier to use than Sculpt. I do promise to play with Sculpt more, though.... Phew! Got longer than I wanted. Anyway, I think Sculpt is a great rendering package, and if I ever get comfortable with it, I'll do some stuff with it. Right now, all that I feel comfortable with it VideoScape (or, as the marketroids at BbB like to call it, Vege-Scape). I can make it do what I want. I'm having trouble getting Sculpt to do what I want. But I'm working on it..... _-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_ Leo L. Schwab -- The Guy in The Cape ihnp4!ptsfa -\ \_ -_ Recumbent Bikes: dual ---> !{well,unicom}!ewhac O----^o The Only Way To Fly. hplabs / (pronounced "AE-wack") "Work FOR? I don't work FOR anybody! I'm just having fun." -- The Doctor