Projection using Formula or increase triangulation.

[CADlalala]

Hi everyone,
I have to project all the faces of a body on a plane in such a way that the all coordinates (x,y,z) of the body become (x,0,sqrt(y^2+z^2))on the plane.
Is it possible to do this using a law formula? I had a look at this potential possibility but it turns out that I have no idea how to do it so I looked for other options. So far I have tried the following:

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1- Create a journal to revolve all the FACES of the body around the Z axis, then cutting this with a plane to get a slice that contains all these points. Problem -> Some faces cannot be revolved (e.g. cylinders, caps etc).

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2- Create a journal to project all the EDGES of the body on the plane following (x,y,z) -> (x,0,sqrt(y^2+z^2)). Problem -> Some edges cannot be projected(e.g. cylinders, caps etc).

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3- Create a journal to project all the POINTS of the body on the plane following (x,y,z) -> (x,0,sqrt(y^2+z^2))and then trying to fit a surface that pass through those points. Problem -> It is hard to fit a surface in complicated shapes.

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4- Save the initial body as VRML in order to get tessellated geometry (triangle coordinates), then create a code to parse the file changing directly the(x,y,z) coordinates of each triangle for (x,0,sqrt(y^2+z^2). It works OK but for some bodies I would need to increase the number of triangles if I want to get a good result (e.g a rectangular face will have only 2 triangles but I would need more triangle for my purpose in some cases).

Do you have any ideas regarding the law formula or how to increase the number of triangles in a face or any other suggestions to help me accomplishing this task?

Please see a picture illustrating the end purpose of this.

Many thanks!
J

 

[CADlalala]

Sorry I forgot the attachment.

 

[petulf]

Huh weird problem

What is it exactly that you need with all these points? Do you only need the silhouette of the part? ie the boundary made by the points? or do you need the points inside the boundary?

If you only need the boundary use the extract command under derived curves. If you for some reason need to map points back from the plane to the volume then a solid mesh of some kind is probably the way to go and it would also be easy to control the element density.

 

[cowski]

Here's some additional info for the OP's problem:

thread561-362683
thread561-364682

www.nxjournaling.com

 

[CADlalala]

Hello,
Thanks for your answers. My final aim is to be able to get the 2D axy version of "any" 3D model. Therefore the outer edges and the boundaries of each internal elements are the important information if we want to put automatically a mesh to that afterwards. For example if we consider a heat exchanger we will need to see the fluid and the solid parts of the model. Please see attached an example of the desired result.
Does it make it any clearer?
Thanks!

PS: To work with silhouette edges would be an option if I could get a "fully revolved 3D body" but actually I can't revolve some faces (e.g. cylindrical).

 

[loki3000]

mesh it with triangular elements (or export to vrml, stl...), export to a text file then edit it with python or a similar programming language as a plain text file.

 

[CADlalala]

Thanks for your answer.
That was one of the things I have already tried (point 4 in my previous message) but in order to make that work I would need to know how to increase the tessellation (number of triangles) in the model. For example a rectangle would only be defined with a minimum amount of triangles (two) but this is insufficient for my purpose as when I project the points {(x,y,z) -> (x,0,sqrt(y^2+z^2))} I only obtain the outer profile without triangles inside it. Please see picture attached.
Is there a way to increase the tessellation in NX when exporting VRML files?
Thanks!

 

[loki3000]

check if it's possible to set accuracy or use another format. STL is quite accurate (or more accurate in that regard).