FreeCAD Sverchok & Subd To Nurbs

Rastart · September 13, 2020, 5:50pm

I found this in the freecad forum…
https://forum.freecadweb.org/viewtopic.php?f=10&t=16982&start=20

Maybe could be interesting

eobet · September 23, 2020, 8:59am

Is that… legal? Isn’t the T-spline technology a proprietary solution that got bought by Autodesk about a decade ago? I’m not sure you’re allowed to reverse engineer it, and even so, I’m fairly certain you can’t call it T-splines?

Please correct me if I’m wrong, because it was a groundbreaking technology that the world lost when Autodesk bought the company behind it!

Rastart · September 23, 2020, 10:28am

I Just find this link of a GitHub project (tspline opensource implementation) in freecad forum, I absolutely don’t have any understanding of this topic, it’s a matter of High level engineering, but it’s interesting that someone in freecad community could implement something similar in the next years… Apparently if there are open source kernels of tspline it shouldn’t be a problem to use them in freecad…

What I m developing in my freetime it’s just a python script to convert pieces of mesh in nurbs patches, then make a coumpound surfaces obj in freecad and then convert in a solid, nothing related to Tspline.
I’m working right now with the sverchock extra nodes to make this process in a Dynamic bridge Blender/freecad, the nurbs silk workspace in freecad seems promising…

Development snapshot:

jimmy.b · August 11, 2021, 6:57pm

HI Folks, I just found this wonderful little Addon,
Which as far as I understand, can convert Subds directly to nurbs/Iges format!
Hurray!

https://www.digital-sculptors.com/cms/index.php/software/blender-plugins.html

brothermechanic · August 12, 2021, 4:08pm

Intresting, but it’s win32 only, not linux

I did search in github

May be someone can port it for linux users?

bkjernisted · August 12, 2021, 5:13pm

brothermechanic, should it work on windows 10 64 bit

pafurijaz · August 12, 2021, 7:05pm

I got an answer from developer and will develop also a version for Linux and for Mac OS

Rastart · August 13, 2021, 5:23pm

The addon seems very powerfull, have you tried it out?

Meanwhile I’m testing a new node for sverchok to approximate subd to nurbs in real time:

There’s no perfect continuity but I improved the approximation adding the central vertex as constraint using the Freecad Surface Filling operator.
https://wiki.freecadweb.org/Surface_Filling

the good things is that subd crease is preserved…
approximate_nurbs_03

Once I’ll get the script working fine I’ll add it to my sverchok branch:

github.com/nortikin/sverchok

add FCStd read and write nodes

nortikin:master ← rastart:master

opened 08:46PM - 26 Oct 20 UTC

rastart

+1436 -2

## new nodes (exchange) FCStd read - import parts from single or multiple fre…ecad project files filter by name feature FCStd read Sketches - import Sketches from single or multiple freecad project files filter by Sketches name FCStd write - write solid or mesh parts in a single freecad project file FCStd Spreadsheet - read/write parameter from a freecad spreadsheet Approximate Subd to Nurbs - convert an obj (with subd modifier) to NURBS ## FCStd read features **filter by name -dropdown enum list** select the part to be imported **read_update -bool** enable/disable reading **read_body -bool** enable/disable reading freecad Body **read_body -bool** enable/disable reading freecad Parts **tool_parts -bool** enable/disable reading freecad parts/features inside a solid operation or body ( it read just the final output) **invert filter -bool** invert filter selection **input-> file path -path** **input-> part list -string** (OPTIONAL: part labes in string list format) **output-> -solid** ## FCStd Sketch read features **mode -dropdown enum list** read mode: only geometry , only construction geometry, both **filter by name -dropdown enum list** select the sketch to be imported **max_points -int** parameter to resample the geometry by set max points in relation the the max geometry curve length **invert filter -bool** invert filter selection **read_update -bool** enable/disable reading **input-> file path -path** **input-> part list -string** (OPTIONAL: part labes in string list format) **output-> -verts** **output-> -edges** **outputs-> -curve** ## FCStd write features **write_name -string** name of the part(s) to be written a suffix `_SV_` and a numeration will be added to the name to avoid delete erroneusly parts in the freecad project. The writed parts will be overwrited on node update. **format -enum** select mesh or solid format **write_update -bool** enable/disable writing **input-> file path -path** solid mode: **input-> -solid** mesh mode: **input-> -verts** **input-> -faces** ## FCStd Spreadsheet **filter Spreadsheets by name -dropdown enum list** select the freecad Spreadsheet **filter Spreadsheets cell by alias -dropdown enum list** select the freecad cell alias in the selected Spreadsheet **write parameter** set the node to write mode **input-> file path -path** **input-> cell in -float** **output-> cell out -float** ## important Code tested both in blender 2.93 (py3.9) and freecad 0.2 (py3.9) More tests required to ensure safe usability. - [x] FCStd read node: needs label list input to filter parts - [x] FCStd Sketch read node: need testing, complete curve translation and a better label... - [x] FCStd read node: write dropdown freecadpart list node - [x] FCStd spreadsheet node: read / write mode - [x] code refactoring - [x] fix for blender 2.93 / freecad 0.20 py3.9 - [x] add an update button - [x] Approximate Subd to Nurbs node added - [ ] Approximate Subd to Nurbs node sorting algorithm improving - [ ] Approximate Subd to Nurbs node debugging - [ ] nodes review / testing - [ ] add docs - [ ] ready to merge ![update_buttons](https://user-images.githubusercontent.com/8501792/119225042-c4707d80-bb01-11eb-99aa-16da210bf461.jpg)

pafurijaz · August 13, 2021, 8:31pm

Very nice these with Sverchok I was never able to make it working on Linux, I hope one day when I have a new PC with a fresh installation, my OS now I think is very messy too many experiments and I can’t wipe every things because I need it for work.

1D_Inc · August 13, 2021, 11:26pm

Indeed, it looks iteresting and very promising)

Rastart · August 17, 2021, 6:41pm

just released the subd nurbs node in my sperimental branch (under EXCHANGE category):
GitHub - rastart/sverchok: Sverchok

here a first test of the node in the blender/freecad bridge workflow… a magik jar…

The code underneath is just a proof of concept, it works but not reliable. It will be necessary to find a better sorting algorithm, right now too many bootleneck related to FOR cycles, so NOT use with complex mesh, for me it crash over 10k mesh ( a 1k mesh is done in few seconds but 6k mesh need few minutes to be converted)

You just need to place on the obj a subd modifier with minimum 2 levels of subd and not update in edit mode.

bkjernisted · August 18, 2021, 9:34am

Rastart, which version of freecad should I install to use the subd nurbs node on windows 10? Which version of blender? Are you posting tutorials on Discord as well? Thanks

Rastart · August 18, 2021, 11:40am

I’m using blender 2.93.1 and freecad 0.19 py 3.9 version, but as far as I know the freecad builds now are py3.8 due to win7 compatibility issues.

BUT using miniconda is very straightforward:

IMPORTANT:
at this time for me the 0.2 dev build doesn’t worked
conda create --name fcenv-dev --channel freecad/label/dev freecad python=3.9.2

THIS WORKED(0.19 stable)
conda create --name fcenv --channel conda-forge freecad python=3.9.2

I would like to open a discord channel on this project but still a lot of work to do, I’ll keep you updated!

bkjernisted · August 18, 2021, 9:43pm

Thanks Rastart for making the video. Sorry it took as long as it did to respond.

yorik · September 2, 2021, 9:12am

@Rastart would you mind if I borrow some screenshots of this thread for the https://www.freecadweb.org/features.php page?

Rastart · September 2, 2021, 9:06pm

Of course!
If you need something more specific to illustrate this Blender/Freecad workflow just ask!

yorik · September 3, 2021, 8:52am

Great, thanks!! It’s basically to illustrate that things are “permeable” between different apps, and I think there is nothing more stunning than this blender/sverchok/freecad workflow

Rastart · September 3, 2021, 11:03am

Absolutely, I Just scratched the surface, but the control you can have on the 3d modeling it’s HOLISTIC and very fast to iterate from the idea to the 3d model until the real object, at work I used BIG 3d CAD softwares and I can say that with some time of sperimentations and implementations this pipeline could be a serious One.
I’ll keep doing some little design likes box & jar but once I will be more confident with new freecad assembly I ll go into some “animatronic” project…
Anyway thanx for your work with FreeCad!

brothermechanic · September 3, 2021, 4:13pm

Super Cool News!
I need to got it!
Thnak you!

1D_Inc · October 16, 2021, 3:49pm

Another free 100% quads manifold surface model for test purposes.
Enjoy)

https://www.turbosquid.com/3d-models/pearlworks-cp145-element-3d-model-1773969