What is Parasolid?

Parasolid is a geometry kernel: the layer inside a CAD system that describes and manipulates faces, edges and solids. Many CAD and CAM systems are built on it or can read its format. Its native file format comes as x_t (text) and x_b (binary). Such a file holds the shape and topology of the model, not dimensions or tolerances as on a drawing. Each file belongs to a kernel version, and older software often cannot read a file from a newer version.

When does an x_t file carry the shape without translation?

Whether an x_t file carries the shape across without translation depends on the system the model was made in. If that system runs on the same kernel, it writes out the geometry as it already existed in the model. If it runs on another kernel, an x_t export is a translation too, with much the same risk of altered fillets or blends as with STEP. On the receiving side, only a system built on that kernel or fitted with a reader for it opens the file.

How does Parasolid work in practice?

When customer and shop both run software on the same kernel, x_t is often the shortest route to a clean solid. If you do not know what the customer models in, STEP is the safer request. Either way, the requirements come from the drawing, not from the x_t file. If your system will not open the file, ask for it to be saved in an older kernel version or for a STEP export.

What is Parasolid often confused with?

Parasolid is not a CAD system: it is the kernel underneath, shared by several. Nor is it a neutral format like STEP or IGES: x_t is one kernel's own format, maintained by that kernel's vendor rather than set in an international standard.