#why did shape twist?
8 messages in this thread
I made a closed path 2D shaper and pulled it out of its plain in the lofter so
it's 3D. But when I previewed and made the object the shape on the path would
twist slightly so they did not match up where the lofting began. I did not have
twist or any deform buttons on. Any ideas why the shape would twist?
——Will
Hi Will,
<< Any ideas why the shape would twist? >>
Check your 3ds.set file for LOFT-BANKING=YES and make it NO. This may be the
problem.
Will,
>>I made a closed path 2D shaper and pulled it out of its plain in the lofter
so it's 3D. But when I previewed and made the object the shape on the path
would twist slightly so they did not match up where the lofting began. I did
not have twist or any deform buttons on<<
I had similar problem, which I posted a few weeks ago, more than once, and got
suggestions such as "make sure banking is off" etc. However, I had already
done that, both on AND off and I never could get the project to work. I got
too busy to pursue it or other simpler variations or work-arounds that I
dreamed up. I have an intuition that this may be a mathematical "bug"…i.e.
paths do NOT like to be pulled into certain 3D shapes, such as a loop. (I was
trying to make a race track with a vertical "Hot Wheels" type loop.) This is
not unique to 3D studio. I found the same problem in an early version of
Playmation (a Stunt plane do a vertical loop would mysteriously flip 180deg
halfway thru the loop.)
I also welcome suggestions….
NOTE to Yost group: IT would be really nice to have the the ability to
manipulate Paths in the 3D Editor with the same tools we have for objects.
Lydell Anderson Anderson Animation
Lydell –
PMJI-
I suspect that I'm kind of catching the back end of this thread – In fact, I
didn't see the original question, only the responses from Jonas and yourself.
If I'm getting this correctly….someone (Will) was trying to loft a simple
shape along a "straight line" path ?! And the resulting mesh didn't loft quite
so straight ?! If this is the case… I've had that happen to me….and it
really "wigged me out" the first time it happened. I had no deform settings
and the path sure looked straight to me. Sometimes, even thought a path may
appear to be straight, it's not. ( It's similar to a Modify\Segment\Refine in
the Shaper – the split segments now contain "curve settings" as opposed to
"linear information" ) In the Lofter….try Path \ Straighten and then
re-loft. The big tip-off for a path that needs straightening – the step marks
are unevenly spread out.
As I said, I missed the original question. Hope this applies to what you were
talking about. If not…(Roseanne Rossanadana) nevermind <G> !
CU
Gary 🙂
Gary:
-well, yes, I think you missed what my problem was, but it may be related. I
was trying to loft a shape (simple thin rectangle) along a path which was three
dimensional. Namely, an oval "racetrack". The rectangle lofted in an oval
with banking "off" in 3ds.set worked fine. Then when I tried to twist the path
mercilessly so that one of the straightaways in the oval had a vertical "hot
wheels" type look, I got 180 degree flips at the far right and far left ends of
my oval track. I don't know if I am explaining this properly, but the other
thing I noticed was that the track did not meet itself normally at the
"beginning-ending" point (it was supposed to be a closed path. I created the
path in the 2d shaper as an oval with an internal loop, then twisted the
internal loop 90 degrees in the lofter. It would have been easier if we had
something like the 3D editor to manipulate paths. To be honest, I haven't
played around with it much, but one other suggestion was to look at the control
point direction arrows. It gets to confusing trying to see 3d arrows in 2d
space.
I think your analogy to the straight line that isn't really straight is about
right on target. The problem is I don't want to "straighten path"
…I want the loop, but not the 180 degree twists at each end of the oval!
Lydell
Lydell –
>> … I tried to twist the path mercilessly so that one of the straightaways
in the oval had a vertical "hot wheels" type look…don't know if I am
explaining this properly…<<
Yea, I don't know if I'm visualizing what you mean…what exactly do you mean
by "vertical hot-wheels look" ? Do you mean the track edges ?
…Anyway…that's probably irrelevant.
>> It would have been easier if we had something like the 3D editor to
manipulate paths <<
Yep…I agree with that to a large degree. There have been a few times that
I've bailed on a model idea because it would require a significantly complex
lofting path or too much time "jacking" with the path…I, too, sometimes wish
there were better tools for editing 3D loft paths… but on the other hand – it
sure seems better than modeling with Autocad ( how I used model ). I suspect
that modeling tools will improve in time…at least I hope it does <BG>.
>> I don't want to "straighten path" << Correct !
>> …I want the loop, but not the 180 degree twists at each end of the oval!
<<
It may not be the most efficient method ….but….how 'bout just breaking up
the model into managable components?…I.E. : loft the oval – minus the
section of the loop…then loft the loop and assemble in the 3D Editor. I
don't know if I'm I over-simplifying your problem? Not a real "clean"
technique but, at least you could predict and control the results.
CU
Gary 🙂
Gary—
>>I don't know if I'm visualizing what you mean…what exactly do you mean by
"vertical hot-wheels look" ? Do you mean the track edges ?
…Anyway…that's probably irrelevant.<<
I don't mean to bog you down on this issue, I was trying to commiserate with
you on YOUR project. But since you asked, by "Hot Wheels Look" I am referring
to the 1960's (dating myself) toy race tracks with flexible plastic track that
could be made into loops, so if your "hot wheels" model car was going fast
enough it would do a vertical "loop d'loop" and it was fun to imagine doing it
in a real car. I was trying to replicate that as a fun project on the side,
but it turned out to be harder than I thought at first brush.
Your idea about separating the loops into two projects, a horizontal and ver
tical loop, may just work. It will be a little tricky since I wanted to use
the same path for the car motion as well as track lofting, and I may get some
jerky spots when I splice the animations. Will give it a go though.
I've been too busy fooling around with Key factory IPAS to do much on this
project (need a 30 hour day)… 🙂 There are more things to adjust on this
IPAS than controls in a 747 cockpit….
Thanks…
Lydell
Lydell –
>> I am referring to the 1960's (dating myself) toy race tracks with flexible
plastic track that could be made into loops, so if your "hot wheels" model car
was going fast enough it would do a vertical "loop d'loop"…<<
"vertical loop d'loop" ?? Why didn't ya just say so in the first place ?!?<BG>
I may lead a sheltered life (don't ALL animators) but, hey !, I'm only 28 – and
I still play with 'em <BG>. Actually, I was confused by the use of the word
"vertical". I thought maybe you meant how the edges of the track are turned up
? Oh well, I follow you now !
>> I wanted to use the same path for the car motion as well as track lofting,
and I may get some jerky spots when I splice the animations. <<
You're probably right….How 'bout a "hard cut" camera change ?? That way
nobody will know the path has "changed" <G> Well, that's the easy way out of
the dilemma…it doesn't really solve your lofting/motion "path" problem
though. If I get a little extra free-time I'm going to mess with this one a
bit…. now you've got me curious.
>> (need a 30 hour day)… 🙂 <<
Be careful what you wish for….you just might get it !! 🙂
>> more things to adjust on this IPAS than controls in a 747 cockpit….<<
I feel the same way about Pennello…
CU
Gary 🙂