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View Full Version : Slicing >all< segments of a Curve simultaneously: CONNECT on multiple seqments?



jeric_synergy
10-09-2015, 12:35 AM
Been playing with SPLINE MODELING lately, found a HUGE bug, but also see a need: Is there a way to create a CURVE, and then add a point to the middle of each segment of the Curve, in one click?

For ONE segment, CONNECT will do this. If you select 2 segments, CONNECT adds a point and connects it together, while changing the Curve to a poly.

I ran thru the Subdivide tools, and several had errors if >2 segments of a Curve were selected, and they were designed to work on polys anyway.

Suggestions? I'm not even asking for interpolation (although that would sure be nice).

EDIT: some posts googled suggested CUT, but it does not work on >2 Edges selected on the same polygons, so, no.

Kryslin
10-09-2015, 01:48 AM
Hmm.
Doing it natively... not in one click (AFAIK). Kill, create 2 pt polys, select edges, extend, connect segments, delete extended edges... It's a lot of work, and doesn't give the desired result of a smooth curve.

It's doable in lscript/python - since Lightwave appears to use Catmull-Rom splines, it's as simple as evaluating each segment at t = .5, and creating a new curve from the old one. It might be easier in Python, since it would (hopefully) have access to the evaluation function for the exact type of CR spline...

I'll give this a go this weekend. Should be interesting.

jeric_synergy
10-09-2015, 02:09 AM
Doing it natively... not in one click (AFAIK). Kill, create 2 pt polys, select edges, extend, connect segments, delete extended edges... It's a lot of work, and doesn't give the desired result of a smooth curve.
Well, 'smooth curve' is negotiable. I'd be satisfied with points averaged between segments. But, if it's doable.....

It's doable in lscript/python - since Lightwave appears to use Catmull-Rom splines, it's as simple as evaluating each segment at t = .5, and creating a new curve from the old one. It might be easier in Python, since it would (hopefully) have access to the evaluation function for the exact type of CR spline...

I'll give this a go this weekend. Should be interesting.
There's some good news! Tnx.

So you know: the deal is, lots of times I'm finding it would just be nice to have segments split to enable more control over the spline, and doing it one by one is a time-consuming PITA. AND since g.d. Knife doesn't work on Curves (now, THAT would be handy, eh?) this sorta stop gap is convenient. (And the fine motor control necessary for twiddly tools like ADD POINTS is getting more and more problematic, whereas Knife is bigger movement-wise.)

From your comments, I guess you know how to construct CC splines?

MonroePoteet
10-09-2015, 04:47 AM
Probably not what you're looking for, but if you select the Curve in Polygon mode, you can use Multiply => Add Points to add control points anywhere you need extra control. You have to be reasonably close to the curve when clicking to add a point.

mTp

prometheus
10-09-2015, 06:30 AM
just curious jeric, why donīt you start using pz bezier more?
it has way more control with segments and handles on a curve, you can use those also for spline patching or lofting with cm loft etc, unless you insist using native tools for some reason?

jeric_synergy
10-09-2015, 08:37 AM
Probably not what you're looking for, but if you select the Curve in Polygon mode, you can use Multiply => Add Points to add control points anywhere you need extra control. You have to be reasonably close to the curve when clicking to add a point.
Indeed.

(And the fine motor control necessary for twiddly tools like ADD POINTS is getting more and more problematic, whereas Knife is bigger movement-wise.)

JoePoe
10-09-2015, 11:36 AM
Use Sensei's Easy Spline ;)

otherwise...

on the extrude option above... I have a slightly different slant.

From spline > Make Pole :hey: (point will be selected) > switch to polys > subdivide smooth > switch back to points (point will still be selected) > expand selection one step and delete > delete cross bar. Smooth if ya gotta and toggle back to spline. (that one point just makes selecting and getting rid of geometry so much easier :))

OPTION 2: Also a couple of steps.... but it'll be perfect.
Change Curve Divisions to coarse in General options > freeze > select point loop > make open curve > delete the poly > select points on curve > nth pattern 2,1 > delete.

spherical
10-09-2015, 11:53 AM
Use Sensei's Easy Spline

Yup. Dead easy and you can go back and forth from polychain to spline.

JoePoe
10-09-2015, 12:20 PM
.......and you can go back and forth from polychain to spline.

for that I use ef Toggle Lines/Curves (https://www.lightwave3d.com/assets/plugins/entry/ef-toggle-linescurves/).
It doesn't have the other functionality, but it's free and for toggling alone it's a huge help. If ya can't buy Sensei's at least you can have that.

Kryslin
10-09-2015, 06:27 PM
Well, 'smooth curve' is negotiable. I'd be satisfied with points averaged between segments. But, if it's doable.....

There's some good news! Tnx.

<Snip!>

From your comments, I guess you know how to construct CC splines?

I've got the math handy, so yes, I know how to evaluate a CC spline. It's not particularly hard, but then again, the moment you mention such things as polynomials, dot products, and trig... eyes around here glaze over.

jeric_synergy
10-09-2015, 07:03 PM
OUt, warlock! --Once we hit calculus, my bwain stopped accepting math.

Kryslin
10-09-2015, 10:53 PM
I've actually got a working prototype of this... Slices up the spline curve nicely... except the interpolation isn't very good. This leads me to believe that the curve may not be a Catmull Rom spline, (Cubic Piecemeal curve), or one of the variations thereof.