how to filter and keep vertical surfaces only?

May I ask how to filter out roof surfaces (normal = [0,0,1]), exposed floor surfaces (normal = [0,0,-1]), and other tilted surfaces whose z component of the normal is not zero so as to keep only vertical surfaces for a closed Brep geometry representing a building massing using only native Grasshopper components?

Thank you!

Replies to This Discussion

Permalink Reply by Daniel González Abalde on November 28, 2015 at 5:11am

If the normal vector of a surface is perpendicular to the vector Z of the world XY, then is vertical.

If (Normal -vector angle- Unit Z) is aprox. 0.5*pi then true.

Permalink Reply by Grasshope on November 28, 2015 at 6:28am

thanks, Daniel! May I ask how this can be applied in a Grasshopper workflow?

Permalink Reply by Daniel González Abalde on November 28, 2015 at 7:01am

You can promote assistance if you accompany the question with files or images.

Permalink Reply by Mahdiyar on November 28, 2015 at 7:06am

Is it what you want?

Attachments:

Grasshope.gh, 11 KB

Permalink Reply by Grasshope on November 28, 2015 at 7:37am

Apologize, Daniel, for not posting a simple demo file to illustrate my question!

Thank you very much, Mahdiyar! I learn the use of the Equals, Or, and Dispatch components.

May I ask why the input for the evaluate surface component need to be reparameterized?

Permalink Reply by Mahdiyar on November 28, 2015 at 8:02am

Actually there is no need to reparameterize this input, but I prefer to calculate the normal vector in the center point of every face, but for planar surfaces there is no need to do this.

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