QuadrilateralRemeshing
From K-3D
Status
Description
Quadrilateral Remeshing for Closed Manifolds
Properties
- input_mesh - Input mesh (mesh)
- output_mesh - Output mesh (mesh)
- material - Surface material (object)
- min_index - Min index (scalar)
- max_index - Max index (scalar)
- gradient_spacing - Gradient spacing (scalar)
- iso_spacing - Iso spacing (scalar)
Example
The idea is to build a new mesh from an existing one using quadrilaterals whenever possible: think of the original mesh as a statue that you cover with regular pieces of any pliable material.
It's based on Harmonic functions for quadrilateral remeshing of arbitrary manifolds paper by S. Dong, S. Kircher, and M. Garland. It's available from http://graphics.cs.uiuc.edu/%7Egarland/papers.html.
Let's start with the following mesh, it's a polygonized blobby object:
The quadrilateral remeshing process requires two end points to build an 'harmonic field' between. Usually the end points are extrema to produce a nice looking output shape. Here are some isoparametric lines linking points with the same field value, or level curves:
Likewise, 'gradient' lines are contructed, perpendicular to the isoparametric lines:
Then faces are obtained linking intersection points:
Changing spacing value between each flow line yields:
Choosing end points other than extrema:
Note
The quadrilateral remeshing tool only works with closed manifolds made of triangles, that is:
- every edge shares exactly two faces
- or every edge has a companion (K-3D internal structure language)
Howto
- Create or load a closed manifold made of triangles only
- Select one or more points (flow start(s))
- Filter with a FrozenSelection
- Deselect all and select another set of points (flow end(s))
- Filter again with a FrozenSelection
- Filter with QuadrilateralRemeshing
- Connect "QuadrilateralRemeshing.Minima selection" to "FrozenSelection.selection"
- Connect "QuadrilateralRemeshing.Maxima selection" to "FrozenSelection2.selection"
Background
Working with 3D models involves fixing of lots of bad polygons by hand and thus usually remodelling the whole thing. Also, many methods of creating model, such as using blobbies/metaballs, 3d scanning etc, produce terrible mesh structures. Moreover, models that aren't mostly quads behave terribly during catmull clark subdivision. Applying the quadrilateral remeshing tool first would be able to correct easily all those issues.
Other free remeshing tools
Eclectic is a Surface Remeshing tool (released under both QPL and GPL) that outputs mainly regular quads.