Thanks Robert :D

The solution you presented in the image means, that I need to add the parameter "curve" on the beginning of the your definition, then right click on it, "Set multiple curves" and select my whole space frame structure in Rhino. Then on the end I need to add the "data" parameter, which will gather all my members under compression?

Like this:

What about the supports and the nodal forces? How can I define them?

By the way the solution you presented is the one that works with Karamba 0.9.06? Karamba 0.9.06 is not compatible with Grasshopper 0.8.0051?

I have no problem in using your solution. Just I am curious: what will be benefits in using the solution in the newest Karamba in comparison to this one?

It's a little bit more. There are sample definitions for download at http://twl.uni-ak.ac.at/karamba/ that basically should provide what you need.

The new release also will contain better learning examples.

Here is a sample structure under self weight:

The green lines are the ones under axial compression.

cheers

Thank you Robert.

The last image you provided is from Karamba 0.9.06 or from the newest version that will be released in few days?

So basically I need to right-click on "Line" parameter, "select multiple lines" and select my whole space frame/truss structure in Rhino?

Then I need to right-click on "Point" parameter, and define the points in Rhine, where the supports will be.

And that is it? What about the nodal forces and choosing points in which they will be taken?

The sample files you mentioned are simple .ghx files. I think we need some sort of at least pdf tutorial or video for Karamba analysis.

I installed newest Grasshopper 0.8.0051 and newest Karamba 0.9.07.

I created the .ghx defintion the way you told me, but for some reason, my deformation does not look like yours. Take a look:

Can you help me? Where am I wrong?

Here are both .3dm and .ghx files:

Hey Najna,

the scale of your structure and the profiles don't match up. You either have to increase your profile heights with 'modify beam' component between 'line to beam' and 'assemble' or scale down your truss.

Hope you get where you want :)

Nice set of components. Could you tell me how you managed to add the drop down option box to many of yourcomponents? Im currently trying to release some components for Excel and the ability to use a dorp down box for optional settings would really stream line my components,

cheers

Thank you for advice. It worked! :)


The thing I am confused now, is the far left member. For some reason, the karamba does not treat it, nor as a member under compression, nor as a member under tension.
Why is that???

I see now. I have a "null" member. It has no force in it.

Sorry for disturbance.

Simple%20Beam%20Karamba.gh

Building a basic model to calibrate for a paper I am working on. I noticed that the length can cause issues with the model results. When it is set to 40m on the first slider, it doesnt work. Then set it to 39.75m and it works. This happens across the whole slider range at random points.

Have I missed something?

J

Thank you for the tip Joshua.

So If I want to lean my space truss on:

2 supports, I need:

1 pinned and 1 roller support?

3 supports, I need:

1 pinned, and 2 roller supports

4 supports, I need:

1 pinned, and 3 rollers supports

5 supports, I need:

1 pinned, and 4 roller supports

...

?

Effectively thats right. If you have two pins in the same support plane then the second pin will restrict the model from utilising the rollers.

Restraint conditions are, in my opinion, one of the trickiest things to understand when you start modelling.

Dear RubberDuck,

Christoph will make a separate assembly of the custome components and publish it on Food4Rhino. But this may take some time.

Clemens

I have set up this model for a Cantilever with a 2kN point load. Displacement is 72m for a 30m CHS 100x3.3. I then set up the same model in SpaceGass and get the following results:

How do you calibrate your models? I am just trying to work it out so I can start using this for my paper on parametric structural analysis.

Hi Joshua - I think part of the problem with your Karamba model may be the document accuracy - If you have a document with [m] units the tolerance is only +/-.001m by default in Rhino; Grasshopper uses these same tolerances.
The theoretical deflection of your cantilever beam is 

delta = P*L^3/(3*E*I)

= (2000 N) * (30,000 mm)^3 / (3*205000 N/mm^2*1173164mm^4)

= 74,844.5mm

So in your image below Karamba is slightly out, but your SpaceGass model is somehow much different or wrong - have you checked your material /section properties?

I did a quick model in Karamba with the document in [mm] units and got a deflection of 73,062.5mm which is only a 2.5% difference from the theoretical answer.  I did a quick model in Autodesk Robot as well and got exactly 74,844.5mm deflection as expected.

Haha good timing Luke!

I am writing a paper on Parametric structural analysis and just ran through all my analysers to see where I went wrong. I have it pretty much the same.

Example - CHS 100mm x 4mm

Deflection Calcs:

Manual - 64.6m

SG - 60.6m

Karamba - 61.5

Egret - 74.3

Now I am CERTAIN Egret is a result of a bug (I sincerely doubt Jon has made an error and it has been playing up on my computer probably because its full of shit).

I ran another model at 50mm depth of CHS to see if they maintain similar ratios. They do. I wanted to check that I could use Karamba and Egret for Galapagos modelling, so they are both pretty good.

Thank you for the check, its good to have a second set of eyes on problems like this.

Karamba uses a Young's Modulus of 21000[kN/cm2] and by default the thickness is 1/30 of the diameter of the tube. For D=100mm this results in t=3.33333 (etc.).

If you set both values according to the hand-calculation below you get the exact result of 74.844504m.

Here the definition:

Hi Josh,

Thanks for the confidence, but I would certainly double check anything computed by Egret (I haven't had the time or opportunity I'd like to progress and validate it).  I did quickly set up your verification model, the file can be downloaded here:

http://www.grasshopper3d.com/group/geometrygym/forum/attachment/dow...

I would suggest updating Egret from http://www.geometrygym.com/downloads , if you do, you should also see a deformation of 74.844504 (my gh definition assumes mm rhino document units).  If you want to send me the spacegass model, I'll take a look at it for you.

Ok here are the modules I have used to verify.

Karamba Cantilever

Egret Cantilever

I just built the same model in SG:

30m Cantilever

Incaste

2kN point Load at end

And drew the section in the section creator based on the Chinese steel manuals (S235).

Any update on when the learning examples will be available? I feel like I just cant set up my modules right.

What type of accuracy or units do people work in for their Rhino file when they work with karamba?

Here is some WIP to share:

Portal Frame Model

Portal Frame Model w/ Galapgos

CSV File for Sections

Deflections are not right at the moment but will sort them out tomorrow. Pretty happy with the models behaviour.

Having some trouble getting a pinned truss to perform. It works if I allow the beams to bend but when its pin jointed it doesn't like it. Any ideas?

Arch%20Truss%20Karamba.gh

Is it because its trying to be pin jointed at the roller and pin supports? If so how do I remove that?

Beams with bending switched off transmit normal force only. A node that connects to such elements has three degrees of freedom. In case of a planar truss add out of plane supports at all nodes (see also subsection 'Bending stiffness' of section 'How to change beam properties' in the karamba manual).

hey guys!

i want to try karamba example out of the manual, but analyze component turns red...

do you have any ideas where the problem is?

it would be nice if you could help me!

Remarkable new version, very exciting developments.  Keep up the good work!

I love the new version, too.

I am especially interested in the feature: "Free-form structure under uniformly distributed loads - optimized cross sections and bending moments:" shown on the last image above. Is this a new feature?
How to automatically apply that uniform load to a free form structure?

Hello Najna,

you can use the MeshLoad-component to automatically generate point-loads from distributed loads.

Is there a plan to make the sectional profiles visible ? currently they all appear to be tubes ?

I-sections should appear as I-sections, Boxes as boxes,...

Please post your definition in case karamba behaves differently.

Best, Clemens

Absolutely great piece of work. I combined it with galapagos and it solved my problem in minutes! That was a 2 day work to export to Sap2000. Thanks for your beautiful work :)

~Moe

I am using Karamba for structural analysis and optimization.  I've  been moving my GH components over to Rhino 5 and I'm having trouble with the Analysis component.  Here are the steps I've gone through (3 times now).

1. Install latest Rhino 5 beta 64-bit.  Keep old Rhino 4 install.
2. Copy over GH component files from Rhino 4 since you cannot specify the install directory when installing GH.  Add GH as a plug in for Rhino 5.
3. Install Karamba Free 0.9.083 to Rhino 4.  I tried to install Karamba to Rhino 5 beta (under C:\Program Files\Rhinoceros 5.0 Beta (64-bit)\Plug-ins\Grasshopper\Components) but when I install no files appear in the directory.
4. Copy all Karamba files to Rhino 5 directory.

5.  Start Rhino 5 and GH.  Karamba appears in the toolbar and everything appears fine, but I receive the below error from the Analysis component:

Error: Solution exception: The type initializer for 'fem.karambaPINVOKE' threw an exception.

Response from Karamba:

Karamba works on Rhino 32bit. It doesn’t do so for the 64bit-Version because the calculation core is a 32-bit-dll.

The next version of Karamba will work on 32 and 64-bit machines.

hi @ll,

i have some probs with opening the example files.

e.g for LargeDeformationFormFinding_1.gh

maybbe you could ubdate - big thanks !

The archive contains an unrecognized object: Line to beam (karamba) {761b7152-1fb9-4b23-af3c-918d9c889da8}

This object cannot be deserialized

The archive contains an unrecognized object: Large deformation analysis (karamba) {346a8101-b0f3-4d61-b0e0-e85cdeb9d289}

This object cannot be deserialized

The archive contains an unrecognized object: Assemble Model (karamba) {fcd0a5ca-c3e5-433b-a2ad-ba41365116fd}

This object cannot be deserialized

hey

i did dl the latest version of karamba @ your old site, so that was outdated . with new version by http://www.karamba3d.com/ it works

thanx

Support Conditions in Karamba

Few months ago, some member posted a preview of the Support Conditions in Karamba. Take a look:

I saved that image, but did not really understand it.

The black round circles, represent the option that should be checked? And what about the white circles? What do they represent?

Also the last part - hinged connections of the truss, I do not understand it. How to achieve the hinged connections among truss members?

Thank you.

hey djordje!

Tx, Ty, Tz represent the freedom of a support to move  in x, y and z direction (T for translate). the same holds for Rx, Ry, Rz but for a rotation around the respective axis.  those directions can also be determined by a reference plane other than the world xyz system.

Black means the degree of freedom is restrained, while white means it is free to move.

the symbols you see in the drawing are possibilities to more apparently visualize a special support situation, e.g. having a member on a rolling wagon etc..

you could also post requests in our discussion forum http://www.grasshopper3d.com/group/karamba/forum rather than on the board ;)

best

ah,

and hinged connections you can achieve either by using the 'modify beam' component and set the 'bending' input to false, or specify it more detailed by introducing 'cross section joints' on specific beam ids where you can set the same properties as for supports for each the start and the end node of a beam separately.

Hi all, where can I find the mkset tool, or where can I get it? I am experimenting with the stitching tools for trusses and need this tool to stitch a number of truss tension members to their corresponding compression member. 

Thanks

K?

it's in the 'Ensemble'-section.

Best,

C

I still cannot find it, do I have a wrong version or is something disabled from layouts?

Thanks K

The component is missing due to an error in my compiler settings. I have sent you a corrected version.

Best,

Clemens

Please send me your machine.id file: Put a license component on the canvas, right-click on its icon and select 'Save machine.id' from the context menu.

Best,

Clemens

Hello,

I`m using karamba for my shell structure. With the analyzis

the displacements are given, the princ. stress do not work, how can

i solve this problem? See the pictures

I get the messages:

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

J. Koeken

Just asked a stupid question, hadnt realized that rhino 4 was 32 bits and was trying to use Karamba 64.