Control Point Falloff

Hi there,

I use Rhino a lot for manipulating surfaces.
Often, it involves moving control points in the Z axis. However, depending on the resolution of the surface or mesh, the jaggedness needs custom smoothing to make a natural surface.

Is it possible to manipulate control points so that there’s a natural falloff in effect? This would greatly reduce the need to smooth the edges of the transforms which appear jagged. This would save a lot of time for such operations.

-Jeremy

there is
_softTransform


https://docs.mcneel.com/rhino/7/help/en-us/index.htm#commands/softtransform.htm?Highlight=softtransform

there is also
_softMove

for point-wise movements - not sure if this helps

https://docs.mcneel.com/rhino/7/help/en-us/index.htm#commands/softmove.htm

Hi Tom, thanks for your reply

I think SoftMove is the applicable command, but it’s not efficient for what I’m doing.

I have used lasso or brush to select defined set of control points, and I want a customisable falloff range for that selection.
Options for falloff could include:
Falloff profile: linear, convex, concave, spline, etc
Falloff distance
Falloff strength
Perhaps Q value.

-Jeremy

sounds like a custom brush in z-brush to me
or mesh sculpting in blender

one workflow that might be interesting in rhino:
set up a material with a displacement map.
set up mapping etc until the displacement is doing the desired transformation
_extractRenderMesh

maybe also CageEdit (using a curve or surface as cage) might do some of your tricks…
(falloff is limited to customise)

kind regards -tom

It does sound like a z-brush like in blender.
Perhaps something similar could be implemented in rhino? Or a rudimentary version perhaps

-Jeremy

‘Customplay Golf’ (2005) I used many years ago to design golf courses had the type of feature I’m really looking for in Rhino. It’s dealing with a mesh, but has custom falloff types and distance.
You can see it in this short video I just made.

-Jeremy

This screenshot explains the idea pretty clearly :slight_smile:

Would something similar be difficult to integrate into the transform capabilities of Rhino?

-Jeremy

did you play with
_softTransform
enable it
shape = smooth
set the radius…

combine it with gumball or even _setPt

the interface is less accessible and the smooth shape is not as balanced as your example.

your wish would be:

  • a more visual Interface for softtransform
  • a custom fall off shape

what do you mean by Q value ?

kind regards - tom

Hi Tom, thanks for the help :slight_smile:

I just played around with soft transform, but yes, I feel that it could be more visual/intuitive.
Setting the radius of the effect in model units is less intuitive than seeing the effect like in the example I provided.
After a preliminary test, there are some things I noticed.

  1. it could be good to have it as an option under gumball; rather than as a command where you have to select the mesh first. This means that for any control point edit, the falloff would take place if the user turned on the option.
  2. when the option is turned on, the user can adjust the falloff and shape on the fly while seeing how it affects the control points selected.
  3. It could be good if control points for nurbs surfaces could also be affected?
  4. so perhaps what I’m looking for here is something specifically for control points for any surface type; something separate from editing the edges/faces of a mesh.

Not sure if this is intended, but in the video below, once the softtransform has taken place, the centre of the gumball is well below the raised control points. I would hope that the gumball moves to the location of the selected points like a normal transform.

I would use SelBrushPoints, SoftTransform, and Gumball.

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Hi Tom,

I apologise if my answer was a bit much.
Regardless of the other control point transform ideas, perhaps the current softtransform might be better if it had two changes. Some visualisation of the falloff so that when you change falloff distance, you can see what it affects. Also, the gumball following the moved points; instead of resetting to the origin of the gumball transformation (see image below).

-Jeremy

This is on the list as https://mcneel.myjetbrains.com/youtrack/issue/RH-30084/Falloff-in-point-transforms
I’ve added this thread in the comments

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