Old / Random Nodes when sending Model to Robot using SSi

Hi, I’ve only just started learning Grasshopper and the SSI plug-in for robot, so apologies if this is not the correct place to post it.

I’m trying to create a grillage of beams orientated at an angle. I have managed to create this and the geometry looks correct in the rhino viewer. Image 1.

However when I bake the model to robot I get a number of extra points that seem to be from previous model configurations, these also appear when I view the decomposed model image 2.

Is there a way to delete/ purge the old Nodes or am I doing something else wrong?

As a sub question, what is the correct procedure for sending the model to robot? I am currently double clicking SSI Bake component but I always get a warning box saying the application is currently busy, when I acknowledge the caution box the model opens?

Replies to This Discussion

Permalink Reply by Jon Mirtschin on January 17, 2012 at 3:00pm

Can you post the definition?

My first suspicion is that maybe you have multiple versions of the same Grasshopper model. Note that all grasshopper documents that are open contribute to the same database (and you can generate some of the data from within Rhino). Would this make sense? The plugin should "release" nodes when recalculating the components, I'm happy to test and advise.

To transmit the data to robot, the SSI Bake button is the correct approach. Unfortunately Robot application is slow to start (the cause of the busy option) and comparatively slow to transmit data (annoying when you have a reasonable size model). If you have Robot already running, the plugin should "latch" onto this process first time you bake. I've heard rumors of a new, faster dotNET API being developed for Robot but no idea when it might be available.

Permalink Reply by Alex Richards on January 17, 2012 at 4:30pm

Jon, thanks for replying so quickly. The work on your blog and in this discussion group is very interesting.

I have had a quick look at that model (now opened on its own) and it seems that the problem was having another document open. Amusing how that little misunderstanding managed to cause me so much confusion today, I had a feeling it was something simple!

Regarding the link with robot. I am now finding that I can send the model to robot successfully. However, if I adjust the grasshopper model, then robot closes? I therefore always end up having to start robot from fresh, it does not seem to be possible to latch onto the open programme?

I am still learning the features of many of the SSI components so I am currently adjusting many of the attributes manually. In the current project, I am trying to model a stressed skin timber grillage using a transformed beam section. The beam cross section is therefore dependent on the spacing of the members. Now this is a bit ambitious especially given my current ability but would it be possible to automatically generate the profile of these sections using a polyline and then assign it as a section profile that the analysis program is able to recognise?

Thanks very much for your help.

Alex

Permalink Reply by Jon Mirtschin on January 18, 2012 at 4:14am

Hi Alex,

Glad it helped. This multi-model confusion matter has evolved from the early version of the tools, when some attributes (such as property section tables) were managed in the rhino document, or you might want to work with imported features from existing models. Legacy support prevents me from changing at the moment, but newer plugins I'm developing (such as IFC and Tekla) work differently in that each Canvas document has it's own specific model.

Which version of Robot are you using, 2012 or 2011? I've had some problems with "updating" a 2012 model, so if you install the version specific to this, it will set a new model each time it bakes. If you are running robot 2012 but are running the 2011 plugin, your observations match what I would see. I will try to set up an example model (or if you can email your work in progress, I will treat the model with non-disclosure).

I have done arbitrary profile section properties for GSA plugin (http://geometrygym.blogspot.com/2011/11/nurbs-to-structural-analysi...), I'm not sure if the equivalent is available to Robot but I will look into it.

Cheers,

Jon

Permalink Reply by Lars Olesen on August 16, 2012 at 8:54am

Hi Jon,

Have you had the time to look into an arbitrary profile section for Robot export function?

I would like to model different concrete columns and beams with shapes as seen below:

I have tried different approaches but none really works for me.

Lars

Permalink Reply by Jon Mirtschin on August 16, 2012 at 10:08am

It seems the only option (within Robot as a user or import from API) is to use numeric values for inertia and area etc. This probably isn't the most satisfactory way to do this. Oasys GSA is one of the few analysis software permitting custom user shapes,

http://geometrygym.blogspot.com/2011/11/nurbs-to-structural-analysi...

Permalink Reply by Lars Olesen on August 16, 2012 at 3:26pm

Hi Jon,

Thanks for replying so fast.

Is it then possible to model other then a rectangular cross section in the ssi and the SDR for Robot when working with reinforced concrete ? Or how would you recommend to model RC columns and beam with non rectangular sections in GG?

In Robot 2012 these "predefined" section for RC is possible.