Forums/Tutorials/3D Printing Tutorials & Tips

Mesh decimation for that low polygon look

David McGahan
posted this on October 09, 2011 16:28

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The faceted low polygon look is en vogue judging by how many design blogs are featuring furniture, consumer and transport products designed with this look.

I tried designing some furniture inspired by this style, but I used a slow method of manually stitching together edges of polygons. Its was a little tedious, looked slightly contrived, it really didn't work exactly how I wanted. It can be much more effective to 3D model a complete full resolution design and then use a filter, script or other function to reduce the polygon count.

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This is a warrior's head I created in Sculptris. Its not 100% perfect, but what we're interested in is generating a good starting point for mesh decimation.

What is mesh decimation? It is 3D modeling terminology for reducing the polygon count - this not only has this an aesthetic function, as in this example, but can be useful in some instances to reduce the size of large 3D models.

I know ZBrush has an excellent decimation feature, but what happens if you don’t own this? This is the reason I keep Blender on my computer. There is software that I consider to have a shallower learning curve and I find easier to use as a result, but Blender has a very complete feature set. Its also open source and free!

I suggest you download the latest version of Blender at http://www.blender.org/ For this tutorial I'm using the 2.59a release.

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Open Blender, press X to delete the default cube.

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Import your document. In this case the warrior's head is a wavefront .OBJ file, so we'll need to import it in as such.

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Select the imported geometry, (Blender's default select is right mouse button)

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Modifier Decimation 1.00 - drag this slider to the left. You can see the polygon count listed.

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Depending on your personal taste and scale that you intend to print your object at, you may want to experiment further. If you want to print really small you may need to apply a higher mesh decimation (lower polygon count) to make the effect obvious.

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For best results you probably want to apply mesh decimation to something larger than 40mm cubed.

Export as an .STL file, at this point I usually check the integrity of the mesh for 3D printing. Meshes need to be 100% watertight for 3D printing - that is all edges need to be aligned and joined perfectly to one another.
Rich Borrett has a good explanation of a water tight mesh: http://support.ponoko.com/entries/20217167-creating-watertight-mesh...