Detect 2D-manifold violations before 3D printing

A lot of 3DTin users are 3D printing fans. Naturally I started thinking how 3DTin can be improved for 3D printing.

As it turns out, not all 3D models are printable as-is. When you are working in a virtual world of 3D modelling software, the designs you can compose are only bound by your imagination. But when it comes to realizing them using a 3D printer, all the parts of the model have to be realistic. Therefore there are set of guidelines for editing your 3D design so that it becomes printable. Take a look at this Shapeways page for an example.

Today I am releasing a feature in 3DTin to address one of those guidelines – namely Manifold violations.

In order to be 3D printable the object has to be 2D-manifold. For example, the following model is not 2D-manifold.

3DTin now supports a review mode where such problems will be automatically highlighted. When you try to export a design from 3DTin, it automatically runs the manifold checks and if it finds violations then it asks you to review them. If you choose to do so, the editor changes into a special review mode where you can clearly see the edges that violate this condition, as shown in the following screenshot.

This comes really handy, when you are working on a large model. Take a look at this brilliant model of a Wolf that one of the 3DTin users created. If you want to print this model, you can review the manifold errors as shown in second screenshot.

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You will see several red edges that point to manifold violations. Once you know their locations, you can modify the model around those edges so that they no longer violate manifold requirements. It can be as easy as adding an additional cube in the gap.

Moreover, the same checks also apply for better smoothing of the model. If your model contains edges like above and if you try to smooth the model, you will see some weird results. Therefore 3DTin now applies same checks when you try to smooth a model.

Consider this model of stairs. Because the two steps meet at the edges, they create a non-manifold object, thus also leading to unwanted smoothing outcome. But with the new checks you can review and fix such issues.

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Give it a shot and let me know what do you think. I don’t have much experience with 3D printing, so feel free to educate me if there are any mistakes.

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