3x3 matrix



  • On 14/01/2015 at 04:24, xxxxxxxx wrote:

    Is there a way to do 3x3 matrix calculation like inverse mat.
    I like to use it, to calculate the intersection of a line and a plane.

    This problem is typically solved by expressing it in matrix form, and inverting it:
     \begin{bmatrix} t \\ u \\ v \end{bmatrix} = \begin{bmatrix} x_a - x_b & x_1 - x_0 & x_2 - x_0 \\ y_a - y_b & y_1 - y_0 & y_2 - y_0 \\ z_a - z_b & z_1 - z_0 & z_2 - z_0 \end{bmatrix}^{-1} \begin{bmatrix} x_a - x_0 \\ y_a - y_0 \\ z_a - z_0 \end{bmatrix}.

    -Pim



  • On 14/01/2015 at 06:32, xxxxxxxx wrote:

    Hello,

    you can invert a Matrix with "__invert__()" or the Python "invert" operator "~" .

      
    inverseMatrix = ~worldSpaceCoords  
    

    You may also take a look at the GeRayCollider that can be used to calculate the intersections of a ray and a poly object.

    best wishes,
    Sebastian



  • On 14/01/2015 at 08:08, xxxxxxxx wrote:

    Originally posted by xxxxxxxx

    Hello,

    you can invert a Matrix with "__invert__()" or the Python "invert" operator "~" .

     
    inverseMatrix = ~worldSpaceCoords  
    

    You may also take a look at the GeRayCollider that can be used to calculate the intersections of a ray and a poly object.

    best wishes,
    Sebastian

    Yes, but that is all for a cinema 4d matrix and that is a 4x4 matrix, not a 3x3 matrix.
    I want to use a 3x3 matrix.

    I know I can use the GeRayCollider, but I want to do it myself.

    So, how to do 3x3 matrix calculations in cinema 4d?

    -Pim



  • On 15/01/2015 at 06:55, xxxxxxxx wrote:

    Hello,

    if you cannot use the existing classes and functions of the API you have to solve this problem like any other problem by implementing your own solution or using a existing library.

    If you want to calculate the intersection of a ray and a triangle you do not necessarily need to handle Matrix objects. There are other algorithms like this one.

    Best wishes,
    Sebastian



  • On 15/01/2015 at 07:25, xxxxxxxx wrote:

    Thanks, i will make my own 3x3 matrix calculation.
    Thanks for the link.


Log in to reply