What are the MULMAT and INVMAT for?

Hello. you can read this instructions in the Inform manual.

The amount of shift for a three-dimensional shift can be obtained by using the MULMAT and INVMAT instructions.

MOVL P010 V=500

GETS PX020 $PX001 --> Stores the current XYZ type value in P020.

INVMAT P021 P010 --> Calculates the inverse matrix of the taught position.

MULMAT P023 P020 P021 ---> The amount of the three-dimensional

I use MULMAT and INVMAT with a vision system when I need to do a three dimensional shift using the SFTON3D instruction. I also use INVMAT to create a camera tcp on a robot mounted camera. Kind of a poor man's external reference point software option.

Most generally these are used when shifting a saved reference position using outside data.

I have 1 application where a robot moves locating pins during changeover. We use mulmat to get the XYZ coordinates of that move in a user frame

An example with a diagram would be super helpful here.

I want to create a Tool Offset SFT3D point (to emulate the TOOL OFFSET option in fanuc)

Quote from TSGIR

MOVL P010 V=500

GETS PX020 $PX001 --> Stores the current XYZ type value in P020.

INVMAT P021 P010 --> Calculates the inverse matrix of the taught position.

MULMAT P023 P020 P021 ---> The amount of the three-dimensional

What was the point of the second line? Could this have also worked by substituting P010 for P020 and omitting line 2?

Yes you can use SET P020 P010 instead of line 2.

With SET instruction you can take a copy from P010 to P020.