CompuServe Thread

#Need IPAS Help

3 messages in this thread
#84239From: M. G. BATCHELORFeb 16, 1994 1:46 PM
Hi Martin, Thanks very much for responding to my inquiry. To make a long story short(er), I ended up creating the effect by creating actual models for the particles / trails, using animated texture/opacity maps, post processing, etc.. However, I did experiment with the IPAS solution quite a bit before & after, out of curiosity. As I previously mentioned in another message here, while I have owned 3DS for quite sometime, I only REALLY started using it a lot recently (after R3 release) for various reasons. I have been doing this sort of thing for about 10 years (7-8 for a living), have done work for some of the larger companies in the world, and perhaps do know 3DS better than a lot of folks by virtue of working with so many 3D programs over time; but I am certainly NOT a master of this particular program yet. So I think, because of that fact, I am missing something here. >> I'll have a bash at answering your questions and relieving Gary. The problem doesn't sound terribly hard (quite intriguing actually), but it's just difficult to explain in words <g>. I assume that I must have used too many words to try to explain the problem, and apparently caught Gary at a very bad time. At the risk of being somewhat insulted again, could I please try to pin YOU down on a few points ? >> I suggest using the shaper and lofter for the tubing. You can then use the same loft path(s) for the tubing for animation also. Do this by importing the path to the keyframer with paths/get/lofter and click on your spurt object. Then do paths/follow for the spurt object – this should keep the spurt object pointed in the right direction as it navigates the piping. Yes, this was my initial approach verbatim. >>You then can make copies of the object and slide all the keys for them maybe 5 frames offset from the one before. Here's where I start misunderstanding I believe. COPIES (editor) or INSTANCES (k/f) ? Do you manually "lay them out" along the path properly oriented ? Or leave all copies or instances at the same spatial position as the original ? (if YES, then I am not clear on this) >>Looks great I just tried it – I had 5 dummy objects following eachother down a lofted tube, offset by 5 frames. Do you mean copies / instances when you say dummy objects or actually dummy objects ? If you mean that there are several copies of the spurt object plus the original, all sharing the same 3D space and traveling down the path in unison, only activated at appropriate times via the slide offset manipulation, then I tried this early on with these results: 1) I could not get the long particle trails (slowly decaying) and oriented parallel with the tube's centerline and curved as viewed over time – which was the main objective. 2) The best result I got was more like "tinkerbell pixie dust" (best way I can express this !) no matter how I oriented the axp, set trail length, etc.. By the way, these best results were achieved using Rain.axp actually. However, not what I needed. 3) There was a problem, even with this "dust" version, with filling the tube volume yet not penetrating the walls. If I had gotten the desired effect, I could have spent a lot more time creating other animated maps (or other techniques) to "hide' the surface penetration, and made enough copies so that the particle vector trails were close enough to fool the eye into seeing a continuous curved trail – but I could not get this far. >>In the next episode we'll discuss how to constrain the spurting particles to the tubes interior. If you're willing, I'm listening and looking foward to the next installment. However, to save you the effort of answering these and other questions (assuming you would), and for clarity's sake – Would it be too much trouble to ask you to u/l a .3ds file of the test you did which looked pretty good ? >> Clue: it's all done with smoke and mirrors <g>. That's the name of this game isn't it ? <g> Which IPAS was it that included Smoke & Mirrors ? <bg> I sincerely apologize in advance for the numerous questions (I learned my lesson well), and the .3ds file would probably be the most efficient and clear way to answer this if you would be so kind. I really appreciate your time. Regards, Bill – MEDIA MAGIC b/t/w – A good example of the desired effect is in the HBO bumper which airs just before many of the movies. I would think that a custom IPAS conforming to the "rules" I've outlined in this thread would not only be useful for this type of application, but for many, including animated handwriting as I've read messages on here before. Anyone Listening ? THANKS
#84448From: MARTIN G FOSTERFeb 17, 1994 3:27 AM
MG, I've been using 3ds for almost 3 years now full-time, so I know it quite well – it's just other 3d program that I'm not familiar with <g>. However, I've just started using Softimage which is certainly an eye-opener and hopefully we'll see some of it's powerful features in 3ds in future versions. Now to answer some of your questions: >> and apparently caught Gary at a very bad time. << Gary's really busy developing more exciting IPAS routines for us, so the rest of us try to alleviate some of his ASOFT workload. I'm busy too developing games, but I just try to tackle a few selected questions when I can. >> COPIES (editor) or INSTANCES (k/f) << instances if the objects have identical materials. If you need seperate materials and types of objects you could make copies in the 3d editor and copy the tracks of the first object to the others (objects/tracks/copy position, rotation absolute). This would place them on the same path. Then you'd just slide their tracks in time individually. >> Do you manually "lay them out" along the path properly oriented ? << shouldn't be necessary since you're copying all the tracks absolutely from one to the others (either in the instancing operation or with tracks copy operation). >> Do you mean copies / instances when you say dummy objects or actually dummy objects ? << I just used dummies as examples. It could have been a box that I created in the 3d editor and then made instances of in the keyframer. The fact they are dummies is not important – it's the principal. >> If you mean that there are several copies of the spurt object plus the original, all sharing the same 3D space and traveling down the path in unison, only activated at appropriate times via the slide offset manipulation, then I tried this early on with these results: << Exactly. Just like a train's carriages follow the same path, only a little later in time from the one in front. If your results were inappropriate then I suspect the whole particle technique is probably not very good for your intended "gaseous" application. My other thought would be to use the animated texture/opacity maps technique. You'd apply the mapping co-ordinates during the lofting procedure so that your colour-cycling bit maps would follow the convoluted path of the tubes. Sounds like you were doing something like this in the end. >> If you're willing, I'm listening and looking foward to the next installment. Would it be too much trouble to ask you to u/l a .3ds file of the test you did which looked pretty good ? << It's easier to answer the questions. Besides my example .3ds file was absurdly simple and didn't show much of anything except objects following a path through a tube one after the other. Nothing more. To constrain the particles to the tube you would need to do the following trick:
#84449From: MARTIN G FOSTERFeb 17, 1994 3:32 AM
1) render your animation fully to a sequence of .tga files. 2) render a still of the tubes with no particle systems in them. Make all your tubes matte objects. Render with alpha and alpha split on. 3) Now using video post, set up 1 queue entry of your sequence of .tga files in an .ifl file (text list of image names). In the alpha column use the rgb mask of the alpha file from your still and turn intensity on. This will cause the overshooting particles to be masked out. If your camera was moving then you'd need to rerender the entire scene with your objects set as matte objects. Anyway, I hope you got the idea.