PVcollada convention for rotations and translations

[ArhurP]

Dear all,

Under PVCollada 1.4.1 format, the library_geometries consider frame and tracker.
These templates make it possible to cover the PV plant.

To do this, one suggestion is to start from a definition in the X/Y plane as proposed in the current standard.
Then, to arrange the templates in their final position, there are two possibilities, either to describe the final coordinates or to describe the elementary operations leading to this position and orientation as follow:

• This corresponds to a translation operation according to the coordinates x, y, y with a vector [tx,ty,tz] for the center of the template: this is done in 04 - TrackersPVC2_with_basic_electrical_layout_v2.pvc in the </library_geometries> section

• On complex terrain, this also requires taking into account elementary rotations of vector [rx,ry,rz]: which requires describing an axis of rotation, a rotation sequence to follow, and an orientation convention as described in the issue PVCollada convention for North/East orientations #1 . In the slide that was the discussion about "Describing system parameters"

The axis of rotation may not coincide with the torque tube poles or there may be no torque tube for example for a fixed tilt system. This is particularly important for systems with trackers since it is necessary to adjust the orientation of the tracker relative to its reference orientation.

In this way it is also possible to apply the same operations on the structural elements and to distinguish between the moving elements (for example: frame, torque-tube) and the fixed elements (posts and motor): if the targeted software take this into consideration.

See the following illustration of a tracker template and then the basic operations giving rise to a PV system (2x2) with simply tx,ty and rz in the plane.

[cwhanse]

Good suggestions. I haven't gotten beyond implementing the data objects intended for the section of the PVCollada XML file.

Are rotations, translation etc. handled by the COLLADA specification, or do we need to do something specific in PVCollada's block within a ?