Topic - ETEREA Pseudo-NURBS for MODO • Updated June 26, 2014

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Update June 26, 2014 • Version 1.1

Just a maintenance update to address the problem with main icon in top bar, that disappears in Modo 801 if you press ALT key. It’s fixed now. This kit remains 701 & 801 compatible.


Hi guys,

here is this small toy, for your entertainment: PseudoNURBS Kit.



You can play with it to feel the experience of draw with a different kind of splines (faked splines, to be honest). And these are better, in my opinion, than the standard Curves or Bèziers that comes within Modo.

Don't try to 'work' with this. It's something created to show/ask for a feature, only. If you try to apply this for real work you will feel frustrated ;-)

Here comes a long post to try explaining why I have done this. Read it. Or not… (and excuse my weak English)

It's just a proof of concept. A way to explain how could be to work with better splines in Modo.

Nope. At all.

It's really simple. Forgive for a moment the pNURBS kit and do this:

— Open Modo
— Go to visibility Options (the small Gear Icon) > Active Meshes, Enable 'Show Vertices, Cages & Guides' - Disable 'Show Selections' also.
— Increase the subdivision level for your active Mesh Item (to 4 or 5)
— Enable Wireframe Mode, add a Custom bright Cyan Color to your wires.
— Enable Pen tool / Type: 'Subdivs' / Wall Mode: 'Both Sides' / Offset: '0.001 cm' / Enable 'Show Handles'
— Draw

Voilà. That is all. This is what you get automatically with the 'Start pNurbs' button.

What 'Finish pNurbs' button does is to convert this SDS geometry to a Pixar.SUBD (that is better to create further operations). If the Pen tool would have a 'PixarSubd' Mode, this won't be necessary.

Of course, this is NOT A SPLINE. It's just a very thin ribbon. But, when you draw it feels and you have a feedback very similar to a NURB-Spline.

All you see in the video (bridge, revolve, weigthing*) is created from these thin ribbons. Using the default tools througt a convenient Macro to enable/disable some tool options.

And the bad news is that you can not do too much with this 'thin ribbon', actually.

(*) To Weight a 'point' you need to select the small EDGE that correspond to what it seem a unique point (TWO points really, with an intermediate edge)

( continues on next post )

Cristóbal Vila

Message edited by Cristobal Vila on 6/26/2014 - 4:23 AM

( comes from previous post )

Imagine that Modo would have a special Spline with these features/ characteristics:

— It could be a variation/spezialization of Pen Tool (or a separate special tool)
— Type: 'Subdivs' (as is now) AND 'PixarSubdivs' (not existent actually)
— Wall Mode 'Both Sides' and Offset '0 cm' (not possible actually)
    Or simply put: Mode 'Spline' (no width)

Then, you could draw with this 'zero-width' ribbon. We could call this 'Subdivided Spline' or 'PixarSubd Spline', instead of 'PseudoNURBS'.

Once you have your 'zero-width' geometry you could convert it to:
— Non-subdivided geometry
— Standard SDS geo
— Pixar Subd geo

Exactly the same behavior that polygons, but with zero width.

Imagine that we could operate with this 'kind-of-spline' using the standard Modo tools (not possible actually, what you see on vide has LOTS of limitations and drawbacks):
— Extrude
— Bridge (this would be a loft between 2 splines)
— Revolve (Radial Sweep)
— Patch
— Tubes (curve extrude, using the same kind of splines for section and path)

And we would get standard poligonal geometry (non subdivided, SDS or PixarSubD)

Apart from the good behavior and feedback with these new 'kind-of-splines' (call them pNURBS or whatever you prefer), which means a good curvature-continuity and much less points to create a well formed curve… we would get the great benefit of a perfect match between the original profile and the resulting poligonal mesh. Something you can see in video.

Ideally we could even dream with a extended toolset:
— Loft between 3 or more pNURBS
— Birails (two 'parallel' paths and a transversal 'section')
— Tubes with a initial and final splines (diferent form, same points)

And more.

And all these tools to generate, I repeat, not NURBS surfaces. Nope. To generate just POLYGONS (flat, SDS or PSUBD). I don't mean to try convert Modo in Rhino ;-)

You would like this?
Me too.

When you draw with this "Pen-WallMode-Thin-Subdivided" standard Modo tool (what it's on this kit), you feel like this 'dream' is really possible. Because it seems so near… And all this occurs INSIDE MODO. This is not made using Rhino or Maya.

For that reason I have made this kit (to play with) and the video. Only as a try to open eyes to what it would be possible.

But it would be necessary to invest on NEW tools. And this is something that only Developers could do. Or maybe some brave programmer, using the SDK (not sure if this would be possible).

Of course, I have not the capabilities to do this. At all.

Hope you find this interesting.

I can not do more. But it has been funny :-)

Cristóbal Vila

Message edited by Cristobal Vila on 12/24/2013 - 12:16 PM

Very kind for you to share with us. Installing now and will give it a go... will be a fun thing to play with today!

Much Appreciated.
Really interesting ideas.

Thanks Cristobal!
Noob here :)
Which folder in windows do i place this in... and which files/folders to put in???
Just place the whole folder eterea_pnurbs in your scripts folder.

Thanks Cristobal for your hard work on this. Looking forward to trying it out.
That is awsome! I hope that Foundry will pick up your idea! When modo will have mesh Fusion it could be very useful for all modeling :-)
Thank you for sharing this Cristobal. Merry Christmas!

Windows 8 Profesional | 64GB RAM | AMD card | portfolio: | twitter: TLechocinski

Great work, Cristobal, thanks for sharing and your efforts on this development!

A merry Christmas indeed! Cristobal for President!
Nice proof of concept Cristobal. And a nice choice of music too.

I do not do much spline modeling but if I needed to, I would love to have curves tools like this in modo.
This is super. I think it is very usable even already.
Bravo, Bravo, Bravo

And Happy Merry Xmas !!!
Very cool. I noticed on your blog post video, you duplicated the pNURBS curve for lofting. I can't see on the screen, what method did you use to duplicate?

Message edited by John Rygielski on 12/25/2013 - 2:07 PM

Thank you for the cool toy to play with!

Thanks for your kind comments, guys.
Glad you like this :-)

Quote from riggles :
Very cool. I noticed on your blog post video, you duplicated the pNURBS curve for lofting. I can't see on the screen, what method did you use to duplicate?

It's this simple Macro that I call using CTRL-D:

UPDATE February 9, 2014: I share here a better version, as script:


# To duplicate selected polys and enable Move tool
# By Cristobal Vila - - February 9, 2014

# Query our Prefs for Copy & Paste Selections
copyDeSelectionState = lx.eval('pref.value application.copyDeSelection ?')
pasteSelectionState = lx.eval('pref.value application.pasteSelection ?')

# Change those Prefs to 'true' temporarily
lx.eval('pref.value application.copyDeSelection true')
lx.eval('pref.value application.pasteSelection true')

# Copy & Paste

# Return back to our original Prefs
lx.eval('pref.value application.copyDeSelection %s' % copyDeSelectionState)
lx.eval('pref.value application.pasteSelection %s' % pasteSelectionState)

# Enable Move Tool
lx.eval('tool.set TransformMove on')

Cristóbal Vila

Message edited by Cristobal Vila on 2/9/2014 - 4:29 AM

Awesome. Having come from Alias and Maya, I have always been extremely frustrated with Modo's curves. I find them relatively unusable and it is a shame. I would love to see nurbs in Modo. Including rebuilding and cutting.

Out of curiosity, you call them Pseudo-Nurbs, what do you mean by that? IE what is the implementation?
Thanks for your words, but, have you read my first and second post, Jonathan?
There is a pretty complete information about what exactly is this ;-)

Cristóbal Vila

Message edited by Cristobal Vila on 1/1/2014 - 10:41 AM

I agree, the difference between point curve and nurbs curve shows it clear, we need that in Modo !!!
I agree too, awesome!
Quote from Cristobal Vila :
Thanks for your kind comments, guys.
Glad you like this :-)

It's this simple Macro that I call using CTRL-D:


# duplicate_polys_in_place.LXM
# To duplicate selected polys and enable Move tool
# By Cristobal Vila -

pref.value application.copyDeSelection true
pref.value application.pasteSelection true
pref.value application.copyDeSelection false
pref.value application.pasteSelection false
tool.set TransformMove on

Cristóbal Vila

Personally, I wouldn't force user preference changes like that. It would annoy the hell out of me if, by running a script, my copy/paste settings got messed up.

Use a script for this, get the values they're currently set to. Then set then to the ones you want and afterwards, set them back to the values you stored.
I agree!
I don't want other users to mess up my general settings!

I remember another script I used in the past that everytime it turns on index visualization of the verts in the viewport...I hate it!!!! :-P
Quote from Jeegrobot :
I agree!
I don't want other users to mess up my general settings!

Well, this was only a response to other user that was asking how I made certain operation in the video. And yes, it's much better to use a Script that store your custom Prefs, but:

— This was a 'dirt & quick' macro that I created long time ago just for myself.
— Until just a few weeks ago I had no idea about how to do those simple tasks with Scripts (and this Macro worked perfect for me, since I know how exactly I have my Prefs)

I have updated my previous post with a better version, as a script that stores and reverts back to your custom Prefs at end.


Cristóbal Vila
Really awesome! As a long time user of Rhino I appreciate the value of this tool set and hope to see it implemented soon. I think Modo would be a power house if we started seeing tools from the vector curve world introduced. Rhino has an amazing set of tools for curve creation and modification, seeing those kinds of controls in Modo would bridge the gap between the two.

Thanks you for sharing, really exciting stuff.

  • French Freelance User living in South KOREA
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Great Improvement of the Curve Tool.
I hate it since a long time and as you mention, Maya got great one since a long time.

Can't wait to use those Loft Curve with Mesh Fusion !

Thanks a LOT Cristóbal !


Thanks for your kind words, Scott and Smoluck! :-)

Cristóbal Vila
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