How to convert an assembly into one solid model (single body) IN cATIA?

Follow these steps

  1. Step 1:

    Open your assembly

  2. Step 2:

    tools> create part from assembly

  3. Step 3:

    Click on the assembly you want to convert in the part tree.

  4. Step 4:

    Click on OK

  5. Step 5:

    Save the new part