Blender - Blender is the open source, cross platform suite of tools for 3D creation.
Ink/Stitch - An Inkscape extension for designing machine embroidery patterns.
FreeCAD - An open-source parametric 3D modeler
Crosti - make your own unique cross stitch design from custom image
MATLAB - A high-level language and interactive environment for numerical computation, visualization, and programming
Embird - Machine-Independent Embroidery Software