Unable to get BullAnt ggConvCurve working? (Convert Curve to Arcs)


I have been using BullAnt “ggConvCurve” to produce pure Arcs and Line from free form planar curves.

The Component worked for many curves, and here is one of my examples:

But for some reason I can never get the component working for this curve 2 here:

Can someone please give me some advice? Much appreciated!


For more in depth explanation of the problem, you can visit here:

BullAnt_Problem_Simplified.3dm (52.5 KB) BullAnt Problem_Simplified.gh (13.9 KB)

@jonm, have you seen this?

Hi @dale, hope you’re doing fine. You might be able to review the response to help me understand the cause of this problem. There is a c# component in this gh document.
BullAnt Problem.gh (14.4 KB)

Thanks for reporting Jeff. I have made a fix in the latest build of BullAnt, if you can please download from downloads page of www.geometrygym.com

Rhino doesn’t return a max distance value from the curve to a line, I don’t know why. I have a wrapper method to handle this, but the component wasn’t always using it.

Note that if the polyline boolean input is true, there won’t be any arcs as a rhinocommon polyline is returned (ie all linear segments). Out of interest, what is the usecase that you want an arc dominated polycurve? We are doing some more advance developments for Infrastructure BIM with more advanced curve definitions (ie alignment or linear positioning curves formed of horizontal and vertical definitions with transition segments). This might or might not be relevant.

Hi @jonm,

I am not able to repeat this (see attached). Can you provide a simple sample (including geometry) that isn’t working for you?

TestDistancesBetweenCurves.gh (6.9 KB)

– Dale

Thanks very much Dale and Jon for the replies!

@jonm Thanks a lot for the BullAnt update!! However, I am a Rhino 5 user, I wonder if you can provide a Rhino 5 version of your update?

To answer your question on the purpose of the arc dominated polycurve. This curve here is related to a long ridge steel member of a project, so the arc conversion is purposed to appropriate constructabilty and fabrication. For the advance BIM definition, am I right to interpret that you are referring to a more detailed level of parametricising the joints between each arc segment? If thats the case it might very much be relevant to this project!


Hi Jeffrey, Sure, we still support Rhino5 but you have to find the installer on our google drive folder, https://drive.google.com/drive/folders/106KKYMu3JMY5_N4Ma_z_02vB95SPL6RM?usp=sharing
You’ll find BullAnt v1.5.04 there.

The use case makes a lot of sense, and was the motivation to create this routine. We certainly have tools to help generate BIM from Rhino/Grasshopper inputs. In particular members to Revit. If you want to detail the joints, this is also possible (but typically done with an application such as Tekla as Revit functionality for this is primitive, although we should have a look if there is better API support in recent builds). Get in touch if you’d like to discuss.

I sent Dale the gh script with internalized curve, but note the original post had the .3dm file.



Hi Jon,
Apologies for the late reply, it was Independence Day Long weekend over here. Thank you very much for the program update, the GG component worked perfectly!
The BIM from Rhino/Grasshopper inputs would certainly be a direction that I would be interested in, I wonder if you could provide more information? A website perhaps, let me know if you would like me to DM you?

Thanks again for following up with my question @dale !

Much appreciated!



Check our youtube channel for various presentations, demonstrations etc, https://www.youtube.com/user/GeometryGym
You can also find explanations, samples etc, on our Technical website, https://technical.geometrygym.com/rhino-grasshopper/revit (alongside Revit you will find IFC, Tekla etc)

Feel free to DM or get in touch with more specific questions or a discussion.