many thanks,
I tried the program "2d projection", it is a bit different from the concept x' = M x, in fact the matrix generated by "2d projection" is not familiar to me....
I understand well that objects are deformed by this transfomation (like circles, ellipses, spline.....), but my idea was to see if it was possible to iterate on all selected objects, and if there is even one coordinate (for example a text) apply the matrix M to the insertion point of the text, for a circle the transfomation is only for the center of the circle, for a pline (or 3dpoly) all the vertices, ...... In this way a bit of everything is transformed.
It is necessary to see the result of the transformation in a real case.