[Bf-committers] ID-properties for subelements: CurNurbs, Curve-points, Vertex...

migius at gmx.net migius at gmx.net
Wed Sep 30 04:01:47 CEST 2009

> On Mon, Sep 28, 2009 at 5:57 PM, Joshua Leung <aligorith at gmail.com> wrote:
> > Also, this brings up the question: why would you want custom
> > properties on such a fine grained level anyway, and would the
> > associated increase in memory requirements be worth it for something
> > that, to me, sounds like only < 1% of all users would ever need to
> > use?
> I'm guessing but given that he is the maintainer for the autocad
> importer, it is probably to more completely support the autocad spec.
> Which would be useful to roughly a 1/3 of our current users, and
> probably 90% of our potential users.
> LetterRip
> _______________________________________________

hi Campbell, hi Joshua, hi Tom,
guessed right,
the idea behind vertex-groups and ID-props for curve-data is:
"working with CAD-data in Blender, especially with 2d-data."

A Curve-object can cover entire 2d-CAD-drawing (geometry), but there is no room for storing individual dxf-properties like LAYER, COLOR, LINESTYLE, LINEWIDTH, GROUP, XDATA etc. I think it could be manageable on the basis of vertex-groups or(and) ID-properties on CurNurb and BPoints level.
With only few Curve-objects the scene stays clean - no pollution with millions of 2d objects. Eventually some performance issues, but guaranteed best compatibility to any blender version.

Recently i have tested Mechanical-Blender fork, but I don't want to go this way: it extends blend file with an new object type: Sketch-object. The blend file can be load into standard Blender, but all Sketch-objects go lost. So, it must be converted to mesh-object every time before it. Such one-way-solutions is not what i would prefer.

I am working on CAD productivity suite "CAD-Tools" for Blender 2.4x (python driven, marginal C part) for a long time and lately have made good progress. For two weeks i have a !working! prototype with UI, based on 2.49b, so i am very optimistic to finish it soon. I will try to prepare a release-candidate for Blender Conference 2009.

Besides better DXF support, the prototype includes many useful tools for 2d and 3d editing, especially:
- storage system for reference-points/vectors/scalars/angles
- storage system for named VIEWs
- storage system for Selection-Sets
- mesh-curve-across vertex selection
- mesh-curve-across vertex editing
- arbitrary Workplanes controlled by named UCS, visualized in 3d-view
- Workplanes support constrains: X,Y,Z,XY,XZ,YZ
- "property panel" supporting UCS
- Geometry-Calculator interacting with geometry in 3d-view
- supporting bigger workspace: up to units
- supporting  big list of objects in the scene: up to 50.000
- circles/arcs editing for curve-objects
- move/extend/trim/.../offset for curves and meshes, 2d/3d
- creator/editor for architectural elements
- and more ...

"CADtools"-edition will be dedicated to commercials: engineers and architects, and i think it will be worth to pay for it. Planning marketing model similar to LWCAD(LightWave).

More details in form of screen-videos soon :)

I don't think i can write stable C code for ID-props/Vertex-groups, so it will be great if someone more experienced do this.
I wonder who could spend time on it. Probably CAD support has too low priority now - everybody is busy with 2.5/Durian.

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