triangle -q

Quality mesh generation by Delaunay refinement (a hybrid of Paul Chew's and Jim Ruppert's algorithms). Adds vertices to the mesh to ensure that all angles are between 20 and 140 degrees. An alternative bound on the minimum angle, replacing 20 degrees, may be specified after the `q'. The specified angle may include a decimal point, but not exponential notation. Note that a bound of theta degrees on the smallest angle also implies a bound of (180 - 2 theta) on the largest angle. If the minimum angle is 28.6 degrees or smaller, Triangle is mathematically guaranteed to terminate (assuming infinite precision arithmetic--Triangle may fail to terminate if you run out of precision). In practice, Triangle often succeeds for minimum angles up to 34 degrees. For some meshes, however, you might need to reduce the minimum angle to avoid problems associated with insufficient floating-point precision.