Interpreting Matrix3D data

[Anonymous]

How do you interpret a Matrix3D's data. What cells are related to translatation, rotation, etc? I'm trying to debug why my translation script puts the object in a wrong position but I do not understand the Matrix 3D's data.

Some helpful information would be:

How is translation of a Matrix set?

How is rotation set?

What other variables of a Matrix used to move an object exist?

[ekinsb · Accepted solution]

The top three rows of the first three columns define the rotation.  The last column defines the translation.  The bottom row isn't used.  What's shown below is an identity matrix.  The x-axis is in the X direction (1,0,0) , the y-axis in the Y direction (0,1,0) and the z-axis in the Z direction (0,0,1) and there is no translation defined so it lies at the model origin.

Here's a simle of example that defines a 45 degree rotation about the Z axis and a translation of (5,10,0). The axes should all be unit vectors and they should also be 90 degrees to each other.

You can also read more about transformation matrices here: https://en.wikipedia.org/wiki/Transformation_matrix

[Anonymous]

Thanks 🙂

[Anonymous]

Google helped me to land on this page as I had no clue what matrix3d was or how to understand what was happening. 

The response from Brian gave me a nudge in the right direction but my ignorance was too great for me to appreciate what he was saying.

I continued with the googles and finally landed here:

https://www.youtube.com/watch?v=0rEz9-6trHw

It's a very basic explanation of rotation matrices outside of a Fusion 360 context. 

The lady speaks slowly and carefully. By the end of the 13 minutes I'd learned a huge amount.

[markSJVQS]

I'm trying to do a shear transformation.

No matter what values I put in the 4x4 Matrix3D, the resulting transformation seems only to do rotations and translations.

How can I achieve a shear (skew) transformation of a BRrepBody with the API?

[BrianEkins]

You can't. Fusion only supports translation, rotation, and uniform scaling of bodies. Other transforms will either be ignored or fail when you try to use them.

I think you should be able to apply any kind of transform you want to custom graphics though.