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#geometryprocessing

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How am I supposed to get any work done when the maths is so pretty! Look at it flutter by like a butterfly!

This is an animation for "biharmonic spline interpolation" (see also: doi.org/10.1007/s11004-011-934).

I'm testing a Julia implementation here which I'd like to use to interpolate the Z-coordinate for meshes that should span a closed curve domain where the x,y, and z are known. Here I created a circle and manipulated the z-coordinates using z=sin(x+a) where a is a phase offset. Next I animated the change of the phase offset to create the wave like motion.

A simple parameterised hexahedral mesh of a cylindrical solid.

Coming soon to #Comodo

github.com/COMODO-research/Com

#opensource #computationalmechanics #geometryprocessing

An animation of a hexahedral mesh for a solid cylinder. The animation shows a cylinder with blue quadrilateral faces on top, yellow ones in the bottom, and red ones on the side. The screen shows 3 sliders. When the first slider is changed the mesh density is increased iteratively (each quad is split into 4 new ones). If the second slider is changed the height of the cylinder is changed and new elements are added to maintain a similar point spacing. If the third slider is changed the radius is changed. When the radius is decreased the point spacing decreases and hence additional elements are also added in the height direction to maintain a homogeneous mesh. This animation therefore shows a full parameterisation of a hexahedral mesh of the cylinder.

Continued thread

Evaluating of simple #additivemanufacturing cost function metrics (build height, footprint area, support volume, overhang area, ... ). The model is rotated and all metrics are computed, next the sphere is "painted" to show the magnitude of that metric for that orientation (sum of the lengths of the black lines as estimate of support material use). This way the sphere provides a nice summary visualisation of which orientations are best e.g. in terms of minimising support material use.

Just a bunny rotating according to a uniform set of directions on the sphere. The bunny is colored towards the "overhang" angle with respect to the ground. The black area on the ground is the projection of the bunny onto the ground (a bit like a shadow). This is a simple toy simulation that computes some metrics relevant to the simulation of 3D printing preparation.

Continued thread

And, yep it works for the Batman curve too. Always an important test.

The left image shows interior triangulation and right image shows exterior triangulation. In both cases the algorithm computes angles on the input boundary segments (blue curve) and creates triangles where the angle is smallest and below a threshold. Next the boundary is updated to include the new line segment introduced by the new triangle, and the point "skipped" by adding this triangle is removed from the boundary list. The process continues until there are no more triangles to add. Here I set the threshold to 180 degrees so you get a fully triangulated state.

Meet the n-trapezohedron.

Recipe: put 2*n points around the equator, and 2 more for the poles. Now form n top faces and n bottom faces (all quadrilateral). Now alter the points so that all faces are planar.

High n-values give spiky diamond like things. But the special case with n=3 produces the humble cube!

More here too:
en.wikipedia.org/wiki/Trapezoh

Nice set of equations describing the shapes:
mathworld.wolfram.com/Trapezoh