Wednesday, August 14, 2013

Creating and splitting solids.

So to further understand how well the planar code works I put together a diagram to show the range of curvature exist in the first pass, then to the right the results of the final planarization process that is within a certain tolerance.


Input non-planar vs output planar surfaces:

This also greatly helps in the fabrication process due to the fact you can't just bend wood to shape with out spring back or breaking. So on the left side here the process of creating a mold just to make One non planar panel vs the obvious cheaper solution to the right.


difference in material usage:


After the approximate planarization of the panels I started work on giving these surface thickness and also mitered edges. The mitered edges are important to make sure the panels fit nicely edge to edge and flush to each other. This will help in fabrication since we can use these edges to make sure the angles are correct when installing.

The protocol for this was first to check the normal of each panel surrounding the main panel. Then adding up the vectors of one of the surrounding panels with the main panel to get the average vector needed to create a plane. The plane is then used to split the solid, and we repeat this process over and over until all 4 sides of the panel has mitered edges. If there are no surrounding panels, the edge then creates a vertical plane instead.

The reason for this was to make sure the edges are planar as well. Normally I would consider just creating a vertex normal to offset the surface, but that presents two issues, 1) the panel that I create have a higher chance of not being the right thickness and 2) the edges will twist from vertex to vertex and be harder to fabricate, especially when i'm not sure of which CNC machine i'll get to use. Of course I understand that there will be tolerances that will keep each panel from perfectly matching either way, but the planar edges will help greatly in fabrication since we do not have access to a 5 axis CNC mill.

here's an image showing the process thus far.
From Revit BIM elements to solid panel geometry for milling.

Two options for fabrication come to mind when thinking about these panels. I could either A) use a table saw, measure the angles needed, and cut, or B) try our luck on the OMAX Waterjet at pier 9. The OMAX brings up a new issue of producing the G-code needed to run the machine, but I will update you guys on that later when I have a better understanding on what it means to export these files.

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