VTK
VTK – Set Scalar Range And Show Different Colors
We will compute the distance to the sphere for every point. Write the distance value to point data as scalars. Set different colors for the different distance ranges.
VTK
Calculate The Signed Angle Between Two Vectors
The angle between two vectors can be calculated by the dot product. We want to find the direction of the rotation. Here are two different ways to get it done. 1、Compute the value of Sine of the angle, then we can judge it’s clockwise or counterclockwise. The value of Sine Read more…
VTK
VTK – Increase Density For Model By Add Edge Points
Here is a way to remesh 3D model, for every edge we can add a few points on it and create new small cells. The old big triangle will be removed from the model.
VTK
VTK – Remesh Model By Add Center Point
Here is a way to increase density for the 3D model, for every triangle cell we can add a center point and create 3 new small cells. The old big triangle will be removed from the model. You can read other relative posts about changing cells.
VTK
VTK – Delete Cells And Create Model Without Invalid Points
Generate a new polyData which has not invalid point. We have to colloct the points that are used by cells and update the point ids in the cell lists. I used binary search algorithm to speed up the process.
VTK
VTK – Remesh Model By Flip Operation
We have to find all edges and judge whether the point is in the circumscribed sphere of another three points, the target edge is used by two cells, it has only one neighbor cell in the other words. Finally, flip the cells as the above image.
VTK
VTK: Cut Model By Surface And Increase Density
But the result of the cutting is not particularly idealistic.
So we have to increase density necessarily.
The left one is the low density model, the right attachment model has higher density in the following image.
Math
Rigid Transformation And The Block Matrix
The affine transform in the 3D world can be represented by a 4×4 matrix. If there is no scale in the affine transform, the vector is translate vector and A is the rotate matrix. The original point’s position is representing by M, the changed point’s position is M’. Read more…
Algorithm
Rotate Angle, Model’s Size In Local System, Boolean Operation, Intersection Circle
Calculate Rotate Angle And Asix Between Two Vectors, Calculate Model’s Size In Local Coordinate System, Boolean Operation For Mesh, Found Intersection Circle Of Two Models.