Real NURBS Modelling

[Anonymous]

I dont even know if this is possible with current GDL structure but this would be the obvious step especially now with the new Rhino, Grasshopper- Archicad connection. Right now the curvatures are simplified polylines which cannot meet real construction purposes. DWG export is also affected by this because floorplan views cannot export curves, splines, circles, arcs.
I just saw a preview of Archicad 20 and there will be a new option to further smoothen the imported geometries. I am curious about it but still i dont think it can replicate real Nurbs and probably will make geometry really heavy.

[Laszlo Nagy]

That preview you saw are real NURBS, since NURBS are now implemented into GDL in ARCHICAD 20. However, NURBS modeling is at this moment still not implemented in ARCHICAD modeling with construction elements.

[Anonymous]

laszlonagy wrote:
That preview you saw are real NURBS, since NURBS are now implemented into GDL in ARCHICAD 20. However, NURBS modeling is at this moment still not implemented in ARCHICAD modeling with construction elements.

Does this mean that NURBS are now new GDL commands and it will be possible to write with text an object with real NURBS ?

[Laszlo Nagy]

Yes, there are new NURBS commands in GDL. See my answer in the other thread:

http://archicad-talk.graphisoft.com/viewtopic.php?p=255028&highlight=#255028

[Anonymous]

laszlonagy wrote:
That preview you saw are real NURBS, since NURBS are now implemented into GDL in ARCHICAD 20. However, NURBS modeling is at this moment still not implemented in ARCHICAD modeling with construction elements.

Thats sounds great if this is the future! So the imported objects are real NURBS but just the graphic appearance can be adjusted from segmentation to smoothness? I see that initially the surface is still like a faceted mesh and changes with the new settings.
Wil we be able to convert any surface from Rhino, Grasshopper into a morph and not just meshes?

[Laszlo Nagy]

OK, so, I don't know if NURBS will be implemented in ARCHICAD modeling as well in the future, I just hope it will be as it would open a lot of modeling capabilities for the program.

About the smoothness of the NURBS surfaces: So, this NURBS topic is rather new to me but if I look at the NURBSBODY GDL command what I can see is that internally the NURBS curves and surfaces are defined as real NURBS curves and surfaces and just for display purposes there is a smoothness parameter that can be set to different smoothness levels. Then, based on the smoothness level GDL approximates the NURBS surfaces and creates the triangulated surface. How well the triangulation approximates the real NURBS surface is based on the smoothness setting. This is what you could see in that clip.
But the point is that internally these are really defined as NURBS curves and surfaces.

The NURBS GDL Object can be converted to a Morph but the resulting Morph will become tessellated based on the current smoothness setting of the NURBS GDL Objects. Although the curves will be correctly replicated by the Morph, its edges and surface will not have NURBS intelligence (since NURBS is not implemented in ARCHICAD 3D modeling, only in GDL).

[Anonymous]

I`m just wondering, how difficult would it be to completely switch to nurbs modelling and display in GDL as well as for the construction elements? Would it require to completely re-write the whole modelling and display engine?
I am not saying that everyone needs to design and fabricate complex double-curvature surfaces but at least to be able to use splines in extrusion profiles and paths, for PRISM, TUBE, etc
I don`t quite understand the current NURBS implementation in GDL, since they cannot be used in the modelling and they don`t even display as such. Is like the information is there but you cannot use it. Or they are just the first step towards something bigger...

[Anonymous]

Constantin wrote:
I`m just wondering, how difficult would it be to completely switch to nurbs modelling and display in GDL as well as for the construction elements? Would it require to completely re-write the whole modelling and display engine?
I am not saying that everyone needs to design and fabricate complex double-curvature surfaces but at least to be able to use splines in extrusion profiles and paths, for PRISM, TUBE, etc
I don`t quite understand the current NURBS implementation in GDL, since they cannot be used in the modelling and they don`t even display as such. Is like the information is there but you cannot use it. Or they are just the first step towards something bigger...

Same thinking here, I also hope they are working on something bigger, ARCHICAD is the only BIM software that is using segments instead of real curves so far, if I'm not wrong. This is a long wish for me, I am not working on organic building shapes, but the segmentation affects me on the modeling and documentation of the projects.

[Laszlo Nagy]

I think changing your 3D Engine from this segmented approach to a NURBS-based approach is a pretty big development task which takes years to do.
But the fact that NURBS are in GDL (in some form) gives me hope that GRAPHISOFT maybe has further plans of incorporating these types of geometries more deeply into ARCHICAD.

[Bruce]

I'm currently working on a project where true curves in 3D are a must. The segmentation is visually distracting, but also means I have to draw dummy curves to place radial dimensions in elevations / sections.

Then there's differing segmentation of morphs vs beams vs complex profiles etc, along with exporting the model for Rhino users. Also, when taking off a detail view, all segmented arcs need to be redrawn.

Just about everyone here (where I'm working) is pushing me to go to Rhino for everything (and I'm supplementing the more difficult modelling components with Rhino), but I'm holding out with Archicad, as it can't be beat for documentation.

Add true curves to Archicad, and with the Rhino-Archicad live link, it would be incredible.