Blog for the RepRap project at www.reprap.org - a project to create an open-source self-copying 3D printer. To get all the early posts on this blog with all the images as a single PDF visit this page.
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Thursday, June 28, 2007
Memory hog is bacon
There has been a problem for some time (entirely my fault) with the RepRap simulation window (on the right above). When the machine is building it also does a virtual build in that window, adding a thin rectangular block for each line of polymer laid down.
Of course, for a build of any size, the number of rectangular blocks grows very large, and Java3D has to keep them all in memory. It eventually runs out of space.
But you can only see the last layer and the layer currently under construction. So I have now amended the software so that it keeps just those layers, and throws away all the ones underneath as they go out of sight. It replaces the thrown-away layers with the lower shell of the object taken from the triangles in the STL file. This shell is easy to calculate, as - when a slice is being taken for a layer of the build - the edges in the slice are precisely the lines across the STL triangles needed to make up the top edges of that lower shell.
I notice that in the right hand display you have what looks like stitchwork around the boundary of the print piece. I also notice that there appears to be an infill track missing from the boundary to each of the enclosed holes. Is that a bug or intentional?
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