Scaling 'sweep' spline sub-object.

By MrTom · 2013-09-27

Description

As part of the Tyre-Tire script I wanted to include an option which would scale the 'Sweep Modifier' custom shape in proportion to changing the radius of the created object.

Whilst a simple 'scale' on the whole object would have done the job perfectly well I was intrigued to see if I could replicate the really easy 'manual' method with some mxs code.

The end result was to add a Linked XForm modifier to the spline object and apply the scale to 'it'......thus scaling the spline sub-object and also updating the 'sweep' modifier.....in real-time.

I have since been reliably informed that this can also be achieved without using the Linked XForm modifier for a more elegant solution.....cue barigazy!

So although a solution is found I very much look forward to seeing the alternative.

Cheers.....(esp barigazy)

Comments (4)

Very nice.....

MrTom · 2013-10-18

Sorry its been a while since you posted that code....had to do some 'real' work for a change.

Nice code there Barigazy, much cleaner than I had managed.

I'll implement it and tidy up my sloppy code with all haste......once I've had a coffee.

Thanks again.

Regards.

barigazy · 2013-10-18

Yup. It's been a while :)
My pleasure
Cheers!

barigazy · 2013-09-27

I already post the solution how to manually extract custom profile from sweep modifier but just in case...

fn extractSweepSection mody = if isKindOf mody sweep do
(
local customSection
if isValidNode (customSection = getNodeByName mody.CustomShapeName) then customSection else
(
customSection = if mody.shapes[1] != undefined do (splineshape baseobject:mody.shapes[1])
if customSection != undefined do mody.shapes[1] = customSection
) ; customSection
)
extractSweepSection $.sweep

,,,

barigazy · 2013-09-27

This is the one of few solutions (maybe someone have better idea) that can solve your problem


fn scaleSpline spl perc: = if isKindOf spl SplineShape or isKindOf spl Line do
(
	fn scaleDist p1: p2: sf: = (p1 + ((p2 - p1) * (sf / 100.)))
	for s = 1 to numSplines spl do
	(
		for k = 1 to numKnots spl s do
		(
			inVec = (scaleDist p1:spl.pivot p2:(getInVec spl s k) sf:perc)
			outVec = (scaleDist p1:spl.pivot p2:(getOutVec spl s k) sf:perc)
			setKnotPoint spl s k (scaleDist p1:spl.pivot p2:(getKnotPoint spl s k) sf:perc)
			setInVec spl s k inVec ; setOutVec spl s k outVec
		)
	)
	updateShape spl
)

Next example shows how to scale star shape 50% that is used as sweep profile

-- example helix spline with star profile
delete objects
guide = Helix radius1:50 radius2:50 height:200 turns:1.5 bias:.2 direction:0 pos:[0,0,0] isSelected:on
profile = convertToSplineShape (Star radius1:20 radius2:10 fillet1:3 fillet2:2 numPoints:5 distort:20 pos:[50,50,0] isSelected:on)
mody = sweep CustomShape:1 ; mody.Shapes[1] = profile
addModifier guide mody
-- scale star shape (profile) 50%
scaleSpline profile perc:50