[Ruby] Surface
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Hello,
i have a plenty of points and want to create a surface with the sketchup ruby api. How do i do this? I dont get a "nice version"..
# points will be read from a file... pts = [] pts.push([0,0,0]) pts.push([0,9,0]) pts.push([9,9,10]) my_face = Sketchup.active_model.entities.add_face pts f_material = Sketchup.active_model.materials[0] f_material.color = "green" f_material.alpha = 0.5 my_face.material = f_materialOf Course, this works, but how do i appendd another polygon? I have to loop, but creating evertime a new face? Actually... faces, polygons, entities.. where are the differences? What about hierachy?
Programming in general is no problem, but i dont get the way of thinking in sketchup in my brain.. maybe there is a good tutorial? (I just found ruby-tutorials (i dont need) or sketchup tutorials (helpfully, but i want to use ruby with it!) and [0] is quite poor...)
Regards,
Hackbard_C[0] http://code.google.com/intl/de/apis/sketchup/docs/tutorial_geometry.html
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This might be better in the Ruby Forum...
Without knowing what you want to end up with it's difficult to see what you want to do...
Let's assume that you want lots of similar shaped faces, then make one and group it, copy the group and 'transform' it to where you want it/them etc...
If you want to colour them do it now and then if appropriate explode the groups into one lump...
What are you trying to do ?
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Ok, I'll start a thread at the ruby Forum, just thought of beeing a newbee in sketchp
What I want to do? Making a Hull.. mhm.. maybe comparing with a terrain... there is a grid and each point has a specific height... and i have to triangulate this grid, but the grid I have is not a regular one, the points aren't equally distributed.
i have points p1, p2, p3,... pN... and I know (p1,p2,p3) has to be a triangle, (p2,p3,p4) has to be a triangle.. and so on. I dont know how to do this with the Sketchup Api
edit
Ah, someone moved this topic - thanks!
/edit -
Do you have to create your own ruby? Is there any reason you can't use an existing script?
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Doing it myself is the better way... because maybe I need this for my master-thesis, however ouf course an existing script (with reference/author) is possible.
But I need the source code too, so that I can adjust it to my needs.
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well, Didier made a script called "cloud.rb" - named because it takes a point cloud and turns it into a mesh. I have no idea what algorithm he uses to decide how to order his 3d points. It can be found on this page:
and scroll down looking for cloud v6.zip. I think he scrambled his script so you can't see the source code, but he might share it with you if you PM him and ask.
Your code looks good though. The idea is right. Find 3 points and add a face. The tricky part is figuring out how to decide what 3 points to add - how to determine their proximity to each other so that you daont have a very messy TIN. But I bet there are published papers out there on this topic if you do need to write it all on your own.
Hope that begins to help,
Chris
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Hi Chris,
This is the Delaunay 2D triangulation algorithm that I used here.
Cheers, -
Oh great, thanks Didier! For more info on delaunay's method, check out the wikipedia page:
So the idea would be to implement that process to determine what order to add the points to make faces. Probably add a face normal check to help make all faces point in the same direction.
Or just Didier's if you can get away with it
It's pretty darn good,Chris
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Thanks for your Replies
But the "tricky part", the algorithm (Delaunay or something like this) is no problem for me.In SketchUp is there something like GL_TRIANGLE_FAN or T_LINE_STRIP? Do I just have to loop the code I wrote in the first post? Or are there possibilities to do it a simpler way? To reduce code? Do it faster?
Hackbard_C
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I think you are stuck with having to loop through the points to find the triangles you want to make faces from. You might be interested in the PolygonMesh class. It looks like it might be able to handle the mesh creation faster than just adding the faces directly.
http://code.google.com/apis/sketchup/docs/ourdoc/polygonmesh.html
@unknownuser said:
The PolygonMesh class contains methods to create polygon mesh structures. This is useful if you need to write a custom importer/exporter in Ruby that works at the level of triangulated polygons. For example, you can determine the triangles that make up a 15-sided SketchUp face by using this class, or write a SketchupImporter that reads a data file, creates a mesh from it, and draws faces based on the mesh.
IT also mentions in al old version of the API that you can pre-specify the amount of points and faces that are going to be added to the mesh to speed up the creation process.
Glad you can work out the delauney bit, I'm sure you'll get the SketchUp API under control in no time,
Chris
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