general:retopo_workspace:auto_retopo

We were first in bringing you the most accurate and efficient automatic routines for adding usable Topology to Sculptural models - both organic and hard surfaced.
We continue to refine these routines to greatly reduce the number of man hours needed to create 3D assets from start to finish - all within 3DCoat.
Once mastered, these automatic tools will often produce completely usable models - ready for texturing and even animation - all with the minimum of manual input and toil.

Auto-retopo got essential update. Now it works correctly with lowpoly meshes as well (even with irregular triangulation with long triangles).
Also it may detect sharp edges even over relatively “soft” voxelized objects. It creates “feature strokes” automatically in this case.
You need to turn on “Hardsurface” mode to enable this sort of detecting. Now voxelize+hardsurface combination really has sense.

AUTOPO: Create edge loops with AUTOPO: This routine creates surface topology based on your specifications given in the following dialogs, and places the resulting polygonal mesh in the Retopo Room.
AUTOPO with Ptex: Runs the routine mentioned above and places the resulting mesh in the Paint Room for painting using Ptex. UV seams and Maps are created automatically.
AUTOPO with MV Paint: Runs AUTOPO and places the result in the Paint Room for painting with the “Micro-vertex” method. UV seams and Maps are created automatically.
AUTOPO for Per Pixel: Runs AUTOPO and places the result in the Paint Room for painting with the “per-pixel” method. UV seams and Maps are created automatically.

There are a few things to note about the AUTOPO tools. It is a good idea to enable symmetry planes to force symmetry during the process of creating automatic topology - (assuming you want a symmetrical object). If the object is not fully symmetrical, the program will keep symmetry only whenever possible. If you do not like the automatic result, you can always go to the Retopo Room to manually adjust the mesh to suit your needs.

Also, when using this function, 3DCoat will automatically create a new sub-object in the Paint tab for each object layer in the VoxTree.

We present a novel approach to remesh a surface into an isotropic triangular or quad-dominant mesh using a unified local smoothing operator that optimizes both the edge orientations and vertex positions in the output mesh.
Our algorithm produces meshes with high isotropy while naturally aligning and snapping edges to sharp features.
The method is simple to implement and parallelize, and it can process a variety of input surface representations, such as point clouds, range scans and triangle meshes. Our full pipeline executes instantly (less than a second) on meshes with hundreds of thousands of faces, enabling new types of interactive workflows.
Since our algorithm avoids any global optimization, and its key steps scale linearly with input size, we are able to process extremely large meshes and point clouds, with sizes exceeding several hundred million elements.

Instant Meshes: This video is a brief overview of the Integration of the “Instant Meshes” Auto-Retopo engine into 3DCoat, as an option to using 3DCoat's default Auto-Retopo engine. For further information about Instant Meshes, please visit the following website of IGL and their more detailed demonstration of it.

Retopology Using Instant Meshes

This is not good quadrangulation at all. But if you don't care about edgeloops and need quads mess quickly use it.

In models where you desire more polygonal density (for displacement purposes), 3DCoat allows you to designate these areas with a “mask”.
You can paint these regions with freehand Brush Tools, or you can make more precise designations by using the “E” Panel tools.

In practice, it is often helpful to allow AUTOPO to determine its topology without assistance - just to see which areas need more guidance - (this applies for Flow Guides, as well). Sometimes “no guidance” produces the best results.

After a first pass with AUTOPO, you will be able to see more clearly which areas need your manual help. It’s easy to get carried away, masking too many areas to be scrutinized by the algorithm.

Flow Guides: When no guides are placed by the user, AUTOPO usually produces good polygon flow throughout the resulting mesh, with no unwanted twisting. However, adding guides which do not reach far enough can result in this unpleasant twisting of edge loops and polygon rings.

The best practice, when dealing with organic shapes that have appendages (arms, legs, fingers), is to start and stop the guide lines before and after connecting joints, where a thinner piece of geometry meets a thicker piece (i.e. where an arm meets a shoulder or an arm joins a hand). In these cases, the guide should be drawn as a continuous line starting before the shoulder and extending beyond the wrist and well into the hand area. Fingers should be given guides that start and the tip and continue beyond the wrist, when possible (the longer the better). This helps eliminate any twisting.

In areas of your model where loop consistency is desired and there are no branching areas, use Through guides, longitudinally and laterally, starting and stopping the guide line outside of the mesh area. These guides will, by default, be straight lines and will serve to slice the model all the way through, saving you the time of drawing separate guides for the front and back surfaces. This type of guide works well in areas like the torso and within the girth of an arm or leg, for example.

When a Through guide is used laterally across an area like an arm, they will form complete loops around the arm.

If you choose one of the more extremely automated options for AUTOPO, (“AUTOPO for Per-pixel”, for example), be aware that 3DCoat will mark and “Unwrap” your mesh in its own automatic way. This can often work out well, producing a UV Map with consistently sized quadrangles throughout but the seams of this UV Map may be awkwardly placed for certain view angles and uses.

When you anticipate potential problems, it may be best to choose the simple “AUTOPO” function and mark all seams and Unwrap your mesh manually, inside the “Retopo Room” before “Baking” your mesh into the Paint Room.

Generally speaking, a hard surfaced model will not be animated in an “organic” fashion, but, if at all, will be animated along discreet “part” lines of construction, (like a robot arm or leg, for example). Even more often is the case that a hard surfaced model will not be animated within itself, at all - but may only remain a static fixture or a model moving through space as a whole unit.
Sometimes a hard surfaced model needs to have concrete divisions of texture space - designating unique texture areas that start and end along designated edges.
Each of these situations may require individual treatment, and are, thus, better achieved by creating topology manually.
However, in those non-animated cases or in cases where a texture will be consistent throughout, (like a rusty boiler or a painted object consisting of one color) - AUTOPO could be the ultimate, time-saving alternative to manual texturing, UV marking and unwrapping.
In these cases, try running AUTOPO by offering, as your only input, the final, desired polycount. Add no Density Shading or Flow Guides. Do a trial pass, letting AUTOPO do all the work - and you may be surprised at the excellent results.
AUTOPO does a surprisingly good job at finding hard surface edges and divisions - relieving you of that responsibility - saving you time and sweat.
If you find yourself needing to add input in the form of Guides or Density Shading, it can be necessary to use Orthographic Projections (front, side, back) - without Perspective, to accurately mark a “Through Guide” or a straight density demarkation.


Auto-Retopo multiple objects as one

Auto Retopo Thin Objects

Auto-Retopo for Hard Surface Models: This video covers some tips for getting the best results when using the Auto-Retopo toolset on hard surface objects.

Auto-Retopo for Organic Models: This video covers some tips on using Auto-Retopo on more complex organic models.

Retopo Room Pt.4: AutoRetopo: This video continues the walkthrough of the Retopo toolset in 3D Coat, but begins a deeper exploration of the new Auto-Retopo improvements. ====Tips==== Quick Start: Auto-Retopo (Generate Mesh): This video concludes the Quick Start series for using Auto-Retopo in 3DCoat. The first video focused on Prepping the High Poly sculpt, and this video demonstrates the process of generating a low to medium poly retopo mesh, using the Auto-Retopo wizard.
Quick Start: Auto-Retopo (Model Prep): This video demonstrates some considerations and techniques for prepping one's model prior to using the Auto-Retopo feature in 3DCoat.

  • general/retopo_workspace/auto_retopo.txt
  • Last modified: 2022/06/13 17:56
  • by carlosan