select points on surface by using graph mapper

Hello, I have another basic question...

if anyone can help, that would be great

what I want to do is to select points from surface by using graph mapper..

In other words, selected points shapes what is showing in graph mapper.

3dm and GH are attached

Thanks

Seung

Attachments:

Surface domain.3dm, 70 KB
Sruface domain.gh, 5 KB

Replies to This Discussion

Permalink Reply by Danny Boyes on April 11, 2012 at 4:26am

One aspect of your project which might be getting in the way is you are using a Trimmed surface for you input. Therefore any reference to its UV will include all the Original un-trimmed surface domain. I would approach this by rebuilding the surface to get an easier frame of reference and then constructing the splitting curve from this.

Attachments:

Srufacedomain_db.gh, 8 KB

Permalink Reply by Seung chul,Song on April 11, 2012 at 4:34am

Thanky Danny

One thing I am not really clear is about conversion from x,y coordinate to U,V

Also, what was the clue to extrude in x direction?

Thanks

Seung

Permalink Reply by Danny Boyes on April 11, 2012 at 4:43am

The XYZ is a crude way to get the UV in to the right format. I could have used an Fx2 component renamed the inputs to u and v and then written in the Formula an expression like format("{0},{1}",u,v) but XYZ will do the job, but I admit it is a tad confusing.

For this case I used X but you may have to come up with a different method maybe using Project and finding the average surface normal as the vector.

Permalink Reply by Hannes Löschke on April 11, 2012 at 5:05am

The XYZ isn't crude at all. The UV input expects a generic point and that is exactly what XYZ creates. It's just that for UV coordinates X is interpreted as U, Y as V and Z is ignored. So the generic 3D point XYZ coordiantes are used to store the 2D UV coordinates. No extra stuff needed, just ignore one dimension.

Generating the UVs with a formula is overhead, because you are generating a string from numbers. At the UV input, this string is parsed back to numbers and used to create a generic point that is then used as described above.

Permalink Reply by Danny Boyes on April 11, 2012 at 5:12am

The only down side to XYZ is that it does create real geometry that has no purpose in the big scheme of things.

Maybe there is a use for a UVW component which behaves like the XYZ but you don't get any geometry.

Permalink Reply by Hannes Löschke on April 11, 2012 at 6:28am

Not true, at least from what I can read from the code.

GH_Point simply wraps a Rhino Point3d. Rhinos Point is a structure holding only the the three coordinate values. GH_Point has the ability to draw a preview in the Rhino Viewport when asked. There is no actual geometry stored other than the Rhino point.

The UV input is of type GH_Point. So whatever you plug into this, the parameter makes sure at this point, that a GH_Point object is created for each valid input object that can be converted to a point. Only difference to the XYZ component is, that input params are not previewed, so you don't see the UV point in the viewport. It's just the same as disabling the preview of XYZ.

Permalink Reply by morteza farhadian dehkordi on April 11, 2012 at 5:40am