Hi OSTexo, it's not possible to have the same control point structure in a true offset curve, to have an accurate offset it goes through a fitting process.

Just offsetting the control points alone does not generate an actual offset curve, in some cases it might be close but also in many cases it's not close at all, see here for an example: http://moi3d.com/forum/index.php?webtag=MOI&msg=3838.23

You might try using the Rebuild command on the offset with a fairly loose tolerance like say 0.1 or 0.05, that should reduce control point density by a lot at the expense the accuracy of the offset.

- Michael

Hi OSTexo.

Well... if I understand correctly, you're trying to do the same thing that I discussed some month ago with my thread
"Lightweight Modelling. A case study." (http://moi3d.com/forum/index.php?webtag=MOI&msg=8135.1)

Here I post now a complex and slow, but good solution to achieve one of that tasks, that is :
construct an offsetted control point curve in a lightweight way, to get almost the same topology of the source curve.

I hope that this material may be useful for someone.

A great think could be to write some sort of script that should do automatically all that manual steps.

Here's the video tutorial I created. It's 155 Mb so if you have a slow connection maybe it's better to download it first.

http://take.ms/qhYFO

And this is the script I wrote some time ago, ExtractCurvesControlPoints.js:
https://monosnap.com/file/qklpik3YOeWOVXMkHEpngtOIObPP0C
(it's based on one Max's script).

Place the .js file into the "C:\Program Files (x86)\MoI 3.0\commands" (for windows users).

Please, let me know what do you think about my tutorial.

See you.

P.S. regarding my previous post.

As I wrote also inside the video tutorial, that manual method is good ONLY if you don't care of accuracy of the resulting curve,
bit it's useful only if you want the resulting curve to have THE EXACT amount of control points of source curve.

See you.

Hello Michael,

Thanks for the explanation, I appreciate it. Would it be possible to adjust the Bulge parameter in the Blend dialog by a snapping point in the work area instead of a slider? If that can be done would it be possible to extend that functionality to a factor and ratio basis? If the onscreen snap is possible an offset can be created to simply be used as a reference. I'm not too concerned about file size, more so about curve and surface complexity. It may be a great reverse engineering tool for imported curve sets.

I noticed that the Blend white paper has a blue ring incorporated in the blend.
http://www.integrityware.com/AdvancedSurfacing/Blending.pdf
- Brian

"""""""I noticed that the Blend white paper has a blue ring incorporated in the blend."""""""""""""

A blend "scaling rail"... Actually, the paper mentions and "unlimited amount"....

Kindof like "loft", but incorporated into the edge blend. This could be a powerful addition.

I guess we'll have to wait till modeling enhancements are back on the table, then see if we still have integrityware or a new kernel also, etc.....

Something like a loft with G2 connection
If so,it open a whole new solutions...just think in car model sessions ;)
Thanks Bem and Burr-the professor-Manator ! :)
M

Hi OSTexo,

> Would it be possible to adjust the Bulge parameter in the Blend dialog by a snapping point in the work area instead of a slider?

It could be possible to do that in the future but it would require support in the C++ back end, it's not really feasible to do just through script editing of the current version.


> If that can be done would it be possible to extend that functionality to a factor and ratio basis?

Could you describe the factor and ratio method in some more detail?

- Michael

Hi Brian,

re:
> I noticed that the Blend white paper has a blue ring incorporated in the blend.

That's a blend mechanism in Solids++ that uses a "derivative field" concept. When I tested it I found it to be problematic, sorry I don't remember the specific details. So MoI's blend function is a custom one I wrote myself, it's not using that particular mechanism.

- Michael

Cool, Michael.

I may have asked before, but is there some way to get the x,y,z value of the Normal Vector at point "p" on a NURBS face/surface?
The Normal could be at iso (u,v) intersection point. A line normal to a face can be manually found on screen...

(My current project is solid sweeps, but the math is very difficult, and scripting can only do so much by itself :-)

- Brian

Hi Brian,

re:
> I may have asked before, but is there some way to get the x,y,z value of the Normal
> Vector at point "p" on a NURBS face/surface?

Sorry, right now there aren't any evaluator functions like that exposed to script. But it's definitely something that I want to add in to v4.

- Michael

Hello,

Factor and ratio are in the first minute of this video:

https://www.youtube.com/watch?v=3dODbVtwY-0

I suppose they are VSR terms, I'm guessing Ratio or Factor refers to Bulge in MoI?

VSR is a great toolset but is held back by the Rhino interface, I can imagine MoI can make similar features highly usable.

Hi OSTexo, thanks for the video link. Yes I think the Factor is the same thing as Bulge in MoI.

But I try pretty hard to avoid really complex UIs with 30 or 40 controls in them like they've got there. But dragging points in the view wouldn't clog things up in the same way so that would probably be feasible.

- Michael

Hello Michael,

I agree 1000% on the VSR interface, it's not very usable. I happen to think an in-view method would be vastly superior anyway since you could snap to other geometry.

You could get away with one more drop down in the Blend interface if you were able to specify continuity per side. Bulge could be specified in interface as well as Ratio, which is likely poor terminology from VSR since it means nothing to the average user. Ctrl and Shift functionality to change Bulge and Ratio (name changed) options per side with appropriate feedback to let the user know their state, but no need for additional interface elements in dialog. Icing on the cake would be being able to drag and snap the blend along the input curves and to create a curve off of an input surface at an angle, maybe snapping that in view to geometry. So one drop down and one dialog slider to get all that functionality sounds close with the only other consideration being a visual state helper.

Hello,

Here's a Blend dialog sample. Terminology, e.g. Ratio should be tweaked, but the structure is there. No need for sliders when the process is in view. Bulge and Ratio run in lockstep by default until key press or manual entry?

Hello,

Or this: