What's the opposite of a grasshopper?

Disclaimer: I have no experience with grasshopper outside of browsing through the tutorials posted on this site.

Correct me if I'm wrong, but one application of grasshopper is being able to take inputs, manipulate the inputs, and generate geometry.

Now here's my problem: I have geometry. I need to know what the inputs are.

For example, let's say I already have some sort of CAD geometry. I can toss that into Rhino. Is it possible to do some fancy grasshopper manipulation to take some rather complex geometries and define certain parts of the geometry such that grasshopper (or another tool...I'm open to anything) can tell me what the geometry is numerically? For example, let's say that I have 50 different chairs. All different shapes and sizes and designs...but chairs nonetheless. Is there a way to define certain basic parameters (dimensions of the seat, dimensions of the seat back, number of legs, dimensions of legs, configuration, wheels/no wheels, wheel diameter, etc...) given my CAD geometry and perhaps a good amount of initial setup and minimal amount of effort to extract the information from each geometry file?

I feel like I'm asking for a lot, but then again I was amazed that grasshopper existed...so....

Replies to This Discussion

Permalink Reply by Chris Tietjen on December 10, 2012 at 3:23pm

Here's a simple example of collecting data from input geometry. Let's say we have 36 boxes, all different sizes and we need to know how much sheet material we need to make them...

You're only limited by your ability to parameterize your criteria in ways that Grasshopper components can be utilized.

Permalink Reply by Vicente Soler on December 10, 2012 at 4:23pm

Permalink Reply by djordje on December 10, 2012 at 4:30pm

Damn, I was terrified when Disney bought it.

Permalink Reply by Tristan Wolfe on December 11, 2012 at 6:00am

Good answer

Permalink Reply by David Rutten on December 11, 2012 at 4:52am

There's a difference between measuring certain properties (that's fairly easy) and reverse engineering the logic behind a shape (that could be prohibitively difficult).

If you have a network that should be able to produce a specific shape, it would in theory be possible to use Galapagos to find out what parameters are needed to get to a certain end result. In some cases this will be fairly do-able, in most cases however it's probably either too difficult or it would take too long.

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by Tristan Wolfe on December 11, 2012 at 6:00am

Thanks for the tip on Galapagos. This looks very interesting!

I didn't expect there to be a simple (or maybe even possible) solution, but I wanted to explore my possibilities.

Permalink Reply by David Rutten on December 11, 2012 at 6:50am

It's a rather interesting problem and I tried to reverse engineer some values for a made-up case. I wanted to know how well Galapagos could approximate a hand-drawn curve using the Region Union of three circles:

It took me a while to come up with a good Fitness Function but eventually I think I managed it. As you see the result is actually pretty good, it took about 5 iterations (1~2 minutes) of the Simulated Annealing solver to get this answer. I also attached the file, though you may not be able to open it even on the most recent publicly released version.

David Rutten

david@mcneel.com

Poprad, Slovakia

Attachments:

FindCurve.gh, 19 KB

Permalink Reply by phillip on December 11, 2012 at 9:16am

Nice one, David! Quite an interesting direction to explore more.

Permalink Reply by Vicente Soler on December 11, 2012 at 3:45pm

Patch, network surface, pipe with variable radius.

Why are you using the Brep CP component? It looks like it's not really necessary.

Permalink Reply by David Rutten on December 11, 2012 at 3:51pm

Yup. And then there's this one for making large collections of related but unique colours.

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by Vicente Soler on December 11, 2012 at 4:23pm

At first glance it looked like it's for this (color schemes), but after reading the labels it seems bit more obvious how it works.

Permalink Reply by David Rutten on December 11, 2012 at 5:09pm

It's very similar (my wheel also supports monochromatic, complementary, triad, tetrad etc. etc.) but this object exports any number of colours picked from the palette you define. So, integers in, colours out.

I wrote something like this way way back for the Molecular PDB importer plugin (now long dead).

David Rutten

david@mcneel.com

Poprad, Slovakia