Maya defector looking for asylum (and help with sweeping a null)-image links-
by Greg Neumayer (GregNeumayer)
on
May 3, 2008 at 6:38:52 pm
Hi All. I'm excited about getting into C4D, but am having trouble sweeping a spline. I've created what's essentially a spring twisted into a loop, and now I'd like to sweep that spline. However, the Sweep NURBS command isn't letting me use a Null group as my second parameter. Is there a way to "bake" or collapse the Helix/Shear/Bend group that creates this spline so that the sweep will accept it? --screenshot link:
http://www.antifreezedesign.com/user/forums/C4Dsweep/needToSweep.jpg
True, I could just stack everything under the Sweep, but my problem is that my needed shear command is distorting my lil' tube. I need to establish the shear to the spline before sweeping it to keep my tube from squashing. Here's the problem image: -- screenshot link:
http://www.antifreezedesign.com/user/forums/C4Dsweep/problemFlattening.jpg
Alternately, if someone who's more skilled at math than I knows a formula that would write this spline in 3D space, would that be a solution? (I'm too noob to know if that's possible yet.)
I also need to connect the ends, which may be another whole learning step unless you've got some quick advice. I don't like how the end of the spline gets flat because it doesn't know where to go.
Thanks for any help.
-Greg Neumayer
p.s. If relevant to your help, future iterations of this "coil" will need to be made of differing revolutions, sizes, and thicknesses.
Re: Maya defector looking for asylum (and help with sweeping a null)-image links- by Greg Neumayer on May 3, 2008 at 6:56:57 pm
Follow-up solution:
Right-clicking the Null group and choosing "Current state to Object" seems to have cleared up the flattening by allowing me to "bake" that null group into a spline.
It looks like because it's baked, I can't tweak it, so I'd still be interested in a formula that would build this spline in one step (which would keep it procedural) if anyone has any info.
Re: Maya defector looking for asylum (and help with sweeping a null)-image links- by Brian Jones on May 3, 2008 at 7:07:00 pm
You don't have to use the Null, both the Shear and Bend can be children of the Helix (the order they are in will make a difference) and that will allow you to sweep Cycloid along the Helix the way (I think) you want.
Re: Maya defector looking for asylum (and help with sweeping a null)-image links- by Greg Neumayer on May 3, 2008 at 7:38:02 pm
True, but it looks like "current state to object" applied to a series of objects doesn't flatten them into one object (seems to make multiple objects). But applying it to a Null converts it to one new spline which allows me to shear the spline BEFORE I sweep it, which results in a non-distorted sweep tube.
...or so it seems so far...
-Greg
Re: Maya defector looking for asylum (and help with sweeping a null)-image links- by Greg Neumayer on May 4, 2008 at 9:26:52 pm
I don't WANT to per se, but that was the only way I could seem to get the sweep to work. Do you know how to get the sweep to accept multiple items? (see my images)
-Greg
Re: Maya defector looking for asylum (and help with sweeping a null)-image links- by Greg Neumayer on May 4, 2008 at 10:18:56 pm
Also, the Shear is actually the part I need to animate, so I'm a bit stumped as to how to retain a circular tube/wire while still animating it's Shear. (The Shear animation need is effectively to "tilt" all of the loops in a clockwise direction (see images). Unfortunately, as in my sample Swept image, you can see that the Shear distorts the object AFTER it's been Swept, which effectively squishes the Sweep tube that makes the coil. In real life, this wouldn't happen, thus my need to avoid it. In real life, the coil is made of something similar to 12 gauge electrical wire, and as you can imagine, wouldn't "squash" on it's own circumference.
So, my solution will need to include a way to animate the distortion, THEN sweep it with a non-distorted cycloid.
(As a hack-solution, do you think I could animate (squash) the cycloid opposite to the shear's distortion to effectively nullify the shear's squashing effect on my wire's circumference?)
Re: Maya defector looking for asylum (and help with sweeping a null)-image links- by Brian Jones on May 5, 2008 at 3:46:04 am
the Shear can't affect the Sweep if you shear the spline. Deformers won't go up the hierarchy (well, other than they deform their parent or objects at the same level in a hierarchy). Check this out, I'm using a circle spline in there not a Cycloid but it should be the same.
