Select Points (Vb)

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Permalink Reply by Damien Alomar on January 26, 2010 at 4:59pm

Any particular reason why you'd like to do this? Is retrieving all the points within a parameter in GH, then passing that to a scripting component not satisfactory? You can do this, but you'll have to use an object iterator and deal with MRhinoObjects as well. It can be done, but I'm just not seeing where the advantage is over just supplying the points through GH.

http://en.wiki.mcneel.com/default.aspx/McNeel/SdkObjectIterator

Permalink Reply by tim williams on January 27, 2010 at 2:34pm

Well, I was trying to put together an Image tracking def. with the goal of having a polyline track the movement of a red dot taken from a webcam (done outside of grasshopper). So once the deff finds the red dot then it uses ModeLabs Bake component (with the boolean set to true) to bake the point everytime it moves to a different location. This is where the script came in. Then the script hopefully would grab each of these points which have been created by the Bake component and create a polyline. Let me know what you think. This could be a good exercise to really help me learn vb.net if pointed in the right direction.
thanks!
-Tim

Attachments:

• ImageTracking.jpg, 118 KB

Permalink Reply by Damien Alomar on January 27, 2010 at 6:55pm

So if I understand your correctly, your reason for wanting to grab all the points in the document is to have a record of the movement of the different iterations of solving this definition. If I do understand correctly, then I think there might be a better way to go about this. I guess you could continue on with your approach, but here's how I would attack the problem...

The main issue here is storing the points from the previous iterations, which I'd just take care of through a text file. Pass the point of the current iteration into a script component along with the path of the text file in question. Read all the existing points that are in that text file, then add the point that's been passed in to the file and the list of points that you've parsed, then make your polyline from your list of points.

Permalink Reply by tim williams on January 28, 2010 at 12:49am

Exactly Damien. The problem is this. I was planning on using processing to capture an image from a webcam every second or so and it would save to the same location and file, overwriting each time. Grasshoppers image sampler is linked to that single image and therefore, almost, has a video feed in grasshopper. But this means that it has the same data path each iteration.
I tried streaming the data file to the .txt but I cannot figure out how to just add to the array rather than overwrite it. Any clues??
thanks so much.

Permalink Reply by Suryansh Chandra on February 1, 2010 at 10:58am

Interesting.. How about reading the txt first, adding new stuff on it through concatenation, and writing it again?

Ouch! just tried it and puts GH into a infinite loop.. because everytime it writes to it, it changes the file attributes, so the file parser detects a change in the object and reads it again and ends the loop with writing it again!

Let me now a try a work around to that..

Permalink Reply by Damien Alomar on February 1, 2010 at 1:44pm

All the reading and writing would need to be done within the same scripting component in order for this to work correctly. If your relying on the parser in the post it notes, then it would certainly go haywire.

Permalink Reply by Suryansh Chandra on February 1, 2010 at 3:50pm

Hmm... I figured (two forced 'end process's later).
There is no way one could use that.

Permalink Reply by tim williams on February 9, 2010 at 11:11pm

This is as far as I am now:

http://www.grasshopper3d.com/video/live-video-in-grasshopper?xg_sou...