Free online converter · no sign-up
X_B to IGES converter.
To convert a binary Parasolid .x_b file to IGES, drop it below and download the .igs file it makes, free and with no account. It runs in your browser, so the file never leaves your computer unless you choose to send it to us, and the IGES is sewn back together and compared with what was read from your file before you can download it. Not every file converts: what cannot be rebuilt exactly is refused or left out, and the page says which.
Your file never leaves your computer unless you choose to send it to us: the conversion runs in your browser.
How to convert X_B to IGES
- Drop the file. Drop your .x_b file on the box above, or choose it from your computer.
- Check the format. Convert to is already set to IGES (.igs).
- Press Convert. The converter writes the faces as trimmed surfaces, then reads them back to check them.
- Download the IGES. The file takes your original's name, ending in .igs. A file that fails the check is not offered.
| X_B to IGES | What happens |
|---|---|
| Reads | Binary Parasolid files (.x_b), parts and assemblies, from Parasolid 12 on. |
| Writes | IGES 5.3 (.igs) with trimmed surfaces, in millimetres. |
| Keeps | Every face keeps its shape, with a cylinder, cone or torus written as a surface of revolution. Every part of an assembly that can be rebuilt exactly, in place. |
| Drops | The joined-up solid, which the program opening the IGES has to rebuild, plus the assembly tree, part names and colours. |
| Checks | Volume, surface area, size and number of solids, after sewing the IGES back together. |
| Costs | Free, with no account and no limit on how many files you convert. |
Before you pick IGES
Binary Parasolid and IGES sit at opposite ends. An X_B is compact and holds a solid, with every face knowing its neighbours. An IGES is long fixed-format text holding surfaces and their trim curves, and the program that opens it works out how they join. If the software receiving the file can take STEP, X_B to STEP is the better file to send. This page is for when it has to be IGES: an older CAM package, a controller's import, or a customer who asks for it by name.
What comes across
Nothing is turned into a mesh: faces go across as trimmed surfaces in IGES 5.3, in millimetres, though IGES describes a cylinder, cone or torus as a surface of revolution. Attributes do not come across, so colours and names are gone, and an assembly's parts all land in one file, each in place. A part the converter cannot rebuild exactly is left out, the page says which, and the file's name counts what is there, as in frame (27 of 31 parts).igs.
How the IGES is checked
The converter sews its own IGES back into a solid, closing gaps of up to 0.1 mm, and compares that with what it read from your X_B: volume to one part in a million plus a 10-nanometre layer over the surface, surface area to one part in 100,000, size to 0.001 mm, the same number of solids. That shows the file closes for this converter. Another CAD system may sew at a tighter tolerance and leave faces apart.
A measured example
We tested this on a 120 x 80 x 30 mm bracket modelled in SOLIDWORKS 2024 (a plate with a filleted, chamfered boss and five holes). On a desktop PC its 12 KB X_B became a 101 KB .igs in 1.1 seconds: more than eight times the size, for the same faces. The check line read: "Verified: the IGES file was read back and holds the same solid. It agrees on volume to 0.0001%, surface area to 0.0001% and size to 0.001 mm, 1 solid in, 1 out." Measured on 5 November 2026. A file this simple is the easy case, not the typical one.
Parasolid files fail more often here than any other format. When an X_T will not convert says why, and what to do instead.
Credits and licences for the projects the converter is built on are on the converter page.
Questions
Why is the IGES so much bigger than the X_B?
IGES is plain text laid out in fixed 80-character lines, and it spells out each surface and its trim curves. X_B is packed binary. On our bracket the IGES was more than eight times the size, for the same faces.
Does IGES keep colours and layers from the X_B?
No. The converter writes geometry only, so colours, names and any other attributes on the Parasolid bodies are dropped.
Will my CAM software see a solid?
It may see loose surfaces. IGES has no solid to hand over, and whether the faces join up depends on how tightly that program sews them. If it offers a knit or sew command, that is what it is for.
Every conversion
| From | To STEP | To IGES | To STL |
|---|---|---|---|
| SLDPRT | SLDPRT to STEP | SLDPRT to IGES | SLDPRT to STL |
| X_T | X_T to STEP | X_T to IGES | X_T to STL |
| X_B | X_B to STEP | X_B to IGES | X_B to STL |
| STEP (.stp) | Already STEP | STEP to IGES | STEP to STL |
| IGES (.igs) | IGES to STEP | Already IGES | IGES to STL |
| STL | STL to STEP | STL to IGES | Already STL |
Quoting laser-cut parts from files like these?
Lasertally is Windows software for fabrication shops. It opens STEP, IGES, DXF and NC1 files, measures the pierces, cut length and bends off the geometry, and prices the part on your own rate card.