Normal vector for plane?

If I have a plane, is there a quick way to get the normal vector? (just a simple plane, no surface, no edges or points).

And then a related question - if I have a planar surface, can I get the normal vector for that? I see the Evaluate Surface component, but I'm not sure how to specify the {uv} coordinate. If the surface is planar, and I'm just trying to get the normal vector, then I don't care which uv coordinate it is.

Thanks!

Replies to This Discussion

Permalink Reply by Thomas Bildsøe on February 5, 2010 at 6:46am

I have a couple of ideas for both:

As for the plane you could use the "plane components" object and select the perpendicular vector.

I usually do one of the following to things to find a surface normal.

1. Use the "area" component to find the centroid, use the "surface closest point" to get the uv-coordinates of the point and then use the "evaluate surface" component as you mention.

2. Use the divide surface component, set the uv's to 3x3 or something and use "list item" to select one of the normals. This can be reworked to find a point close to the one you're looking for. The reasen for using this methov over the one mentioned in 1. is that in 1. the normals can sometimes be flipped.

Best regards
Thomas

Permalink Reply by Matt Gaydon on February 5, 2010 at 7:40am

Hi Chris

As noted below by Thomas quickest way to get nomal vector for a plane is the Plane Components Component.

In reply to your second question see tread linked below, which used the MD Slider to denote the UV Input into a evaluate surface component. Note: you will need to Reparameterise the input surface/s in the S input of the evaluate surface component

I have been using this process very successfull on Single and collection of planar surfaces

Hope this helps

Matt

Permalink Reply by Danny Boyes on February 5, 2010 at 8:14am

Hi Chris,

have you tried the Plane Components component?

This will decompose a Plane properties Origin plus X,Y and Z vector. It will also work on Planar Surfaces

Vector>Plane>Plane Components

Danny

Permalink Reply by Chris Wilkins on February 5, 2010 at 8:24am

Thanks all for the Plane Components. That's exactly what I was looking for. I hadn't tried that one because I mistakenly thought it was a "make a plane from components" sort of thing. Quick scanning the toolbar doesn't always tell the whole story.

Thanks Matt for the MD slider with reparameterize. I hadn't tried the MD yet, and this is a perfect use for it.

-Chris

Permalink Reply by Dieter Toews on April 12, 2011 at 10:35pm

I believe that you can just use the plane any where you would use a vector and it will automagicaly assume to mean the normal to the plane :-) (I don't think this works for surfaces though)

RSS