Grasshopper

algorithmic modeling for Rhino

Hi everyone!

I'm trying to convert a Karamba model of a gridshell to SCIA (a software package for finite element analysis). In karamba I use the orientate beam component to change the Z-orientation of my beams. For this I use a reference surface on which I find the closest point to the midpoint of a beam in my gridshell. This point is then used to find the normal vector on the reference surface which I can then use to orientate said beam.

The problem arises when I want to recreate the same structure in SCIA. In this program I need to define the rotation of the local coordinate system (similar to the Alpha input of the orientate beam component). I've tried to recreate the local coordinate system as defined by karamba using the definition below. From this I thought I could compute the angle between my original LCS vector and my rotated LCS vector, thus giving me the input I need for SCIA.

As you can see in the small definition below, I was able to mimick the LCS of Karamba using some vectors, but this method is not consistent. For some beams it works, for some the coordinate system is flipped.

My question is, is there an easier way to extract the local axes from the Karamba model, or easily convert the new Z-axis to a rotation angle?

Unfortunately I cannot share the file for the gridshell itself as it is an ongoing project. Hopefully someone can still help me with this issue.

Thanks in advance,

Steven

Views: 2043

Replies to This Discussion

I do not know if this helps but try using the disassemble component in karamba to get all the lines oriented as they are in the karamba model. Then use a Perp frame and measure the angle between the newly defined LCS (karamba) and the initial one.

Dear Steven, 

I am pretty sure that the Disassemble element component lets you output the LCS of your karamba model, i.e. the vectors for all three directions as defined by karamba.

Hi Steven,

The Karamba to IFC exporter that I've developed should preserve orientations (and other structural analysis attributes), and then you can import the IFC file into Scia using my translator.

Refer to 

http://www.grasshopper3d.com/group/karamba/forum/topics/karamba-exp...

Utilities can be downloaded from http://www.geometrygym.com/downloads

Cheers,

Jon

RSS

About

Translate

Search

Photos

  • Add Photos
  • View All

© 2023   Created by Scott Davidson.   Powered by

Badges  |  Report an Issue  |  Terms of Service