This is an archive of CompuServe forum messages from 1985 to 1995, as saved in transcripts by John Foust.
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>>the SPLINE function in RTAG I haven't used RTAG yet… maybe someone else will jump in and answer… >>"velocity", you really mean "speed along the path" Yes Read action !
I had a thought on this velocity issue you've been tossing about. Howabout using a spline to map the velocity curve you want and maintain speed per unit time (ie. frame) to get the current position in your spline path. You might have an animation that is not frame oriented…
>> The main point was create alot of spline points, and then use >> the one that is closest to where you want to be. That way you can >> have a variable velocity. So… Because the SPLINE function in RTAG can interpolate points inbetween, I will actually supply only…
>>When _I_ was a kid … we didn't even *have* stone tablets. Everything was molten. We just swam around all day… >>And we _liked_ it too! Back to reality (well, not *exactly REALITY* but…), sorry my message came out as a stream . I was composing it on line. The…
Mark, If you enjoyed Eric's "stream of conciousness physics", wait'll Jeff Bowermaster gets a little free time and starts his poetry going again . Stick around… you'll see what I mean. BTW: The stone tablets broke too easy. And you think harddisks are bad… Read action !
Boy… Thanks, for the comments and ideas, guys… I guess . Eric — Think all that went a little too quick for me. I'll be sifting through that for a while yet. Your "stream of conciousness" approach to physics is a new one for me I must say… You have…
Mark, Boy, what a perfect segue! I've been meaning to drop a hint about "3-D Computer Animation" by John Vince (Addison-Wesley, ISBN 0-201-62756-6). I picked it up this weekend and have been learning a lot! Very well written. He explains the basics, but doesn't sugar-coat the important stuff. It's also…
Mark, > I can't see POV-Ray on an Apple IIe, can you? (I guess that dates me > pretty well, eh?) When _I_ was in high shool, , the latest thing in personal computers was the Altair. It used 8 rocker switches for input, and eight LEDs for output. It…
For direction, try LOOK_AT(SPLINE(T+1)) or LOOK_AT(SPLINE(T+1)+SPLINE(T)-SPLINE(T-1)). I think the second one will giver better results. In order to vary the speed, you can calculate 100 times as many spline points, and then increase T by SPEED/100 (and use int(T) in all SPLINE statments). For a rollercoaster, SPEED = sqrt(H-Y). Where…
> It has occurred to me many times that if I knew about POV-Ray and Polyray in > highschool, I would've paid much more attention in calculus class. No kidding… Now I kick myself in the behind when I'd actually like to put that knowledge to work. Although I can't…
I'm not sure if this will give the right effect or not, but here's the acceleration: SPLINE(T+1)+SPLINE(T-1)-SPLINE(T)*2 Where T=Time (Frame number) and SPLINE(T) is the current X,Y,Z coordinates. You may get better/smoother results if you average the look_at and acceleration values for 2 or 3 frames before you use them.…
Mark, As Chris says, you've got the right idea on steps 1 and 2. At least that's what I did using RTAG on a simple "roller coaster" animation, and it worked quite well. Sharp turns can get the view swinging wildly left/right, though. As for rolling, you're on your own.…
Chris – Thanks for sanity check on this… Is this something that you've done before? I think by biggest challenge will be in finding the direction and magnitude of the acceleration vector along the SPLINE path. Do you know of any decent sources that might help me better understand the…
Items 1 & 2 are the way to go. Use location and look_at. Also sky is your best bet rather than rotate but I'm not sure the best way to do it. Perhaps you could compute an accelleration vector, add it to sky and normalize it. There is 1 Reply.…
#Camera "flight" with POV
Message #20578
Perhaps some of you can help me out with a rather interesting problem… (Seem to remember something like this out of my 2nd year Physics book…) I'm intrigued with the idea of creating an animation which emulates the pitch, yaw, and roll of an airplane in flight. (Classic animation, right?)…