There is an issue when absolute altitude is desired, as the folder contents must be forced to share the same style before making the adjustment, thus losing the imported color, which is based on the model color.

If you eventually allow import of differently colored polygons, this approach would lose all that information when the altitude is edited for reset to absolute.

I suggest that the converter allow making the choice.of altitude mode: relative or absolute, and that the altitude of the center point be recorded automatically along with the coordinates.

I've tried several models and noticed a tendency to crash during sessions of multiple import/export. All such models opened and exported fine after reopening Petrichor.

SMcQ