Kangaroo Surface Minimisation

Replies to This Discussion

Permalink Reply by Daniel Piker on March 16, 2011 at 11:56am

Yes, it is possible to do surface minimisation without Weaverbird - just make a starting mesh with plenty of faces in Rhino. There is some discussion of this in this thread:

http://www.grasshopper3d.com/forum/topics/how-to-create-nodesbone

Permalink Reply by Natalie Chelliah on March 17, 2011 at 8:04am

Hi Daniel,

 

Thanks for the discussion link. I have had a look through and although people seem to be using weaverbird on the definitions I have tried to adapt it so it will work without using this. I lofted some circles together to create tubes and then joined them all together and converted it into a mesh. I then inputted this into the definition you posted to the other thread - and tried to adjust it so it would work. However when I try to run it, the final mesh button fails to collect anything. I think it is a problem to do with what is plugged into the connections part of the springs button.

 

Would you mind having a look for me?

 

Many thanks in advance!

 

Natalie

Attachments:

• surface minimalisation 1.jpg, 172 KB
• surface minimalisation.jpg, 184 KB

Permalink Reply by Wiktor Kidziak on March 17, 2011 at 8:21am

Can you upload the file with the mesh you are using? Maybe I can help.

Permalink Reply by Natalie Chelliah on March 17, 2011 at 8:26am

Here they are - thanks!

Attachments:

• Surface Minimalisation 1.3dm, 231 KB
• surface minimalisation.ghx, 189 KB

Permalink Reply by Daniel Piker on March 17, 2011 at 8:29am

You need to input a set of curves into connections to turn into springs. Usually the edges of the mesh.
If you can't access Weaverbird you could use something like what is shown in the attached image. It basically does the same thing as WB's extract edges and extract vertices components.

Attachments:

• mesh_extract.png, 40 KB

Permalink Reply by Natalie Chelliah on March 17, 2011 at 9:40am

Thanks, I tried what you suggested to extract the curves from the mesh. This works when plugging it into the connections part, however after trying to run the simulation I get a runtime message from the Kangaroo engine:

'Solution exception: Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: Index.'

And again the end mesh button fails to collect data. I cant seem to see what is going wrong - one odd thing I noticed though is when I preview the Anchor Points, they seem to be weirdly in the middle of the tube - this cant be right?

 

I will keep going with it but any suggestons are very much appreciated!

 

Thanks

Permalink Reply by Natalie Chelliah on March 17, 2011 at 9:42am

screenshots:

Attachments:

• surface minimalisation try 2 all.jpg, 395 KB
• surface minimalisation try 3.jpg, 326 KB
• surface minimalisation try 2.jpg, 205 KB

Permalink Reply by Daniel Piker on March 17, 2011 at 10:08am

I suspect this is due to how you are building your mesh from separate parts, and the vertices not matching up or being duplicated.

remember that there is no need for your starting mesh to be curved - it is generally easiest to start with the simplest possible mesh with the right topology (number of holes and handles). So usually just simple boxes - try making a mesh box with 10 faces in each direction and copy it several times and boolean them together.

The main part of the mesh will round out when you start relaxing it. The rounded ends will take a little more care, but would be possible.

Permalink Reply by Wiktor Kidziak on March 17, 2011 at 10:13am

I think the way you build up your mesh is a bit wrong. I am not sure what exactly you are trying to achieve but I made an example for you.

 

Attachments:

• SurfaceMinimalisation1wk.3dm, 400 KB

Permalink Reply by Natalie Chelliah on March 17, 2011 at 10:30am

Thanks so much for all your help.

 

Wiktor - Thanks for the example file, yes that is the effect I am trying to achieve. I donwloaded your example and set the mesh in my definition as the first box mesh - but I am still getting the same runtime error - would you mind having a look? Just to clarify, the boolean toggle should be set to false when running the simulation yes?

 

Thanks again

Natalie

Attachments:

• surface minimalisation[autosave].gh, 44 KB

Permalink Reply by Wiktor Kidziak on March 17, 2011 at 10:43am

try this definition insead.

Attachments:

• stretchedfabric001.ghx, 172 KB

Permalink Reply by Natalie Chelliah on March 18, 2011 at 6:07am

Thanks! I have just managed to get weaverbird on the computer I am using at Uni. I have run the definition you posted and also the one Daniel posted here: http://www.grasshopper3d.com/forum/topics/how-to-create-nodesbone.

 

However for both I get the same message before the definition opens (3.jpg) - something about a chunk being missing?

 

Then when I try to to run the definition some odd shapes are coming out...not what i expected. I have included screenshots of both.

 

Thank you so much for your help and sorry for being a pain with this!

 

Natalie

Attachments:

• 3.jpg, 321 KB
• 2.jpg, 2.5 MB

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