Is there an easy way to copy or detect a sketch silhouette from an image?
I almost want to say that it's almost easier when the image is complicated by tracing splines on top, but then as soon as it's geometric it's arc, straight line and so on...
A JPEG image can be inserted into the background of a sketch via the following 2 methods:
1) Use the dedicated function of the ISDX (Interactive Surface Design) module. This is by far the most practical because the operation is direct and this function allows you to automatically resize the JPEG to respect a given dimension between 2 points.
2) Create a flat surface and press the JPEG onto this surface via a texture with mapping. For this there is no need for a module, and by playing with the size of the surface and the scale factor of the mapping you can also respect the imposed dimensions.
info retrieved here http://cadxp.com/topic/24984-inserer-une-image-de-fond-dans-une-esquisse/