In this post we will look at Instant Meshes, an Open Source automatic retopology algorithm that achieves 100% quad meshes quickly and easily, with minimal user intervention.
When designing in 3D, it is common to prefer meshes consisting only of quads since, in general, smoothing algorithms produce better results, are easier to animate, and even to texture.
The process of changing the mesh of a 3D object to one with approximately the same shape is called retopology. Although there are various tools for performing topology and in recent times they have evolved rapidly, it is usually still a laborious process.
There are also tools that perform retopology automatically, but usually the result is not very good, so it is still necessary to do a very important part of the work manually.
This promises to change with the appearance of Instant Field-Aligned Meshes, an algorithm presented at SIGGRAPH Asia 2015 developed by Wenzel Jakob, Marco Tarini, Daniele Panozzo, Olga Sorkine-Hornung that substantially improves results and speed of existing automatic topography tools.
Instant Field-Aligned Meshes allows for the automatic retopology of any mesh to 100% quads with surprisingly good results. However, it is also possible to orient the solution by indicating the flow of the mesh manually, and finish with the automatic process.
Using Instant Meshes
Using Instant Meshes is really simple. In this case we will see the use of the standalone application, but the basic operation is the same for all systems that implement the algorithm.
First, we load a mesh. The formats available in the standalone application are Wavefront Object (.obj), Stanford PLY (.ply), and Aligned point cloud (.aln).
We select the topology options we want and click “Solve”. Instant Meshes makes an initial approximation of the orientation of the mesh, based on the estimated flow automatically.
Next, we can modify or refine the flow of the mesh using the “orientation field” and “position field” tools. These tools act by “painting” strokes that indicate the orientation of the mesh.
Finally, we click on the lower “Solve” button. Instant Meshes performs the calculation and displays what the result of the retopology will be. If we agree with the result, we finally click “Export Meshes” to export the final mesh to an output file.
Instant Meshes has additional tools such as the treatment of poles and singular points. We can move these points to the area of the mesh that interests us, or even cancel one with another. For more information, refer to the program’s documentation.
It is a very interesting and intuitive tool that is worth at least taking a look at. It represents a great improvement over other automatic topology solutions, and in many cases completely avoids the manual process.
Instant Meshes is an Open Source project. The project information and documentation is available at http://igl.ethz.ch/projects/instant-meshes/ http://igl.ethz.ch/projects/instant-meshes/, the code is published on Github at https://github.com/wjakob/instant-meshes.
It is also available as a standalone application in the form of precompiled binaries for Windows, Mac, and Linux. Finally, it has been integrated into the latest versions of Blender (from 10.2 onwards) as an automatic topology tool.