Changing Data

I am analyzing the JensenMechanism to understand how it works and I ran into a strange issue, Thank you for your help understanding this phenomenon. How does the output data change after leaving one component and before entering the next input component? In the attached screen shot the panel shows what is being output from EVAL C (7.841,-0.94,0.0). Then when I mouse over the the P input (base plane of circle) in the following component, the input value has changed to (0.0,0.0,1.0,0.0). Why did this change? I have also attached the GH file in case you need to examine it.

thanks
Stan

Attachments:

JansenMechanism_Phenom.ghx, 590 KB
screenshot.rtf, 9.6 MB

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Permalink Reply by Benjamin Golder on November 6, 2009 at 12:18pm

The data is being converted at the input. More specifically, it is being converted from a point (made up of three float values) to a plane (made up of a normal vector, with a referenced origin). If you look carefully, you will notice that 1.0 is the third value in the base plane input. This indicates that the normal vector of the plane points in the z direction, with an amplitude of 1.0. if you input a point where a component asks for a plane, the default conversion is to convert that point into the origin of an xy plane, which is what has happened here.

If you put one type of data into an input that requires a different type of data, then the data will be converted to the appropriate type if possible. There are certain default conversions that occur when the data being input does not contain enough data to describe the data that is required. In the situation you have described, you have provided enough information to determine an origin for the plane, but not enough information to describe the orientation of that plane. In the absence of information about the orientation, grasshopper substitutes a default orientation: xy.

Keep in mind that while this can be confusing, it can also save you an enormous amount of time when making large definitions.

See the attached image for more examples of data conversion.

Attachments:

ScreenHunter_02 Nov. 06 11.07.jpg, 97 KB

Permalink Reply by Stan Carroll on November 6, 2009 at 1:04pm

Wow! What a great explanation. I totally get it. Thank you for taking the time to do such a thorough job of laying this out. You da' Man.

Thanks,
Stan

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