Several realization ideas of automatic adding support for three-dimensional model

1. Overview

This period of time began to contact with the slicing software. Automatic support has always been the pursuit of a function, here to write their own implementation of the two automatic support, not the best, as a reference to provide to everyone, but also as a memo.

This article focuses on finding the point where the model can add support, and how to add support after the support point, you can refer to the B9 Add model method, or the CW early code to add support method, the two are the same. 2. Two kinds of ideas and key algorithms 1. Based on triangular one-sided midpoint

This approach is to obtain a triangular patch that satisfies the added support, and then calculate the geometric midpoint of the triangular patch as a point where support can be added. For very dense triangular patches, we need to use a hash algorithm to classify these points in a square way. The following figure:

As above, the different points are categorized according to the grid, and each lattice corresponds to a unique identity.
With the above information, select the corresponding point in each grid, or generate a new point based on the points in the lattice.

Here the hash algorithm, just for the two-dimensional plane of a meshing classification. The following figure is the test program:

After the grid classification of different points, we can do a number of operations, such as tree support, such as the average, to find the corresponding support points. With the support point, the next step is to add support action. 2. Ray-Based approach

This method is much simpler to make before it.
Only need to put the model into a bucket angle (look up model), and then according to a certain law (a certain distance per interval) to generate a ray, Ray if the intersection with the model, then find the corresponding focus, and the point as a support point to save, and then the next step with this point to generate the corresponding support structure. Similar effects are shown in the following figure:

As you can see, the resulting support is evenly spaced and neatly arranged:

3. hash algorithm source

This hash algorithm in the slicing software, the optimization of the process is also useful, the purpose of optimization is to repeat or close to the three-dimensional coordinate points to be excluded or combined to become the same point, so that the STL data can be redundant. You can refer to the related actions in Optimizenmodel in curaengine for implementation.

Reference:

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