I am using vtkTraingleFilter to triangulate a vtkUnstructuredGrid.

My goal is to generate a smooth color map. My understanding is that I need more triangles to do this. For example a linear quadrilateral is rendered with two triangles, but I want it to be rendered with say, eight.

How do I achieve this? I was hoping to simply increase the number of triangles that vtkTriangleFilter generates but that doesn’t seem possible. (I am using Activiz btw).

Smoothing after triangulating is not what I want either, as I don’t want smoothing along cell boundaries.

I think vtkLinearSubdivisionFilter will subdivide the triangles, but it’s not what I want exactly. Consider a standard linear isoparametric quadrilateral element. When twisted, it takes on a smooth shape due to the quadratic terms in the shape functions. However, VTK by default decides to use two triangles for this element, resulting in a kink. What I want is the triangulation to use more triangles, placing the extra vertices at positions evaluated using the shape function for that cell.