#### 4.2.11 TLIST Files

The conventional suffix for a `TLIST` file is `.grp` ("group") or or `.prj` ("projective" matrices).

Collection of 4x4 matrices, used in the `transforms` section of and `INST` objeto.

Syntax:

         TLIST			# key word

         <4x4 matrix (16 floats)>
         ...				# Any number of 4x4 matrices

`TLIST`s are used only within the `transforms` clause of an `INST` objeto. They cause the `INST`s `geom` objeto to be instantiated once under each of the transforms in the `TLIST`. The effect is like that of a `LIST` of `INST`s each with a single transform, and all referring to the same objeto, but is more efficient.

Be aware that a `TLIST` is a kind of geometry objeto, distinct from a `transform` objeto. Some contexts expect one type of objeto, some the other. For example in

         INST transform { : myT } geom { ... }

myT must be a transform objeto, which might have been created with the GCL

         (read transform { define myT 1 0 0 1 ... })

while in

           INST transforms { : myTs } geom { ... }
           or
           INST transforms { LIST {: myTs} {< more.prj} } geom { ... }

myTs must be a geometry objeto, defined e.g. with

           (read geometry { define myTs { TLIST 1 0 0 1 ... } })

A `TLIST BINARY` format is accepted. Binary data begins with a 32-bit integer giving the number of transformations, followed by that number of 4x4 matrices in 32-bit floating-point format. The order of matrix elements is the same as in the ASCII format.