Tritangent Fillet

This task shows you how a tritangent fillet is migrated into CATIA V5 using the option CATIA_SPEC.
Open the document FILLET-TRITGT.model in CATIA V5.

  1. Apply a Check AS SPEC on *SET1.

  1. Copy and Paste Special *SOL1 into another CATPart document using the CATIA_SPEC option and update your document to compute the geometry.

You have access to the model's geometry and specifications. CATIA V5 has created a tritangent fillet feature.

To sum up :

V4 to V5 Migration

SPACE Elements
Cuboid Pad/Pocket
Cylinder Pad/Pocket
Sphere Shaft / Groove
Cone Shaft / Groove
Torus Shaft / Groove
Revolution Shaft / Groove
Prism Pad / Pocket
Pipe - Center Curve Rib / Slot
Pyramid Solid Datum
Sweep Rib / Slot
Sweep Spine Solid Datum
3D Sweep Rib / Slot
Sweep Until Solid Datum
Sweep non close Solid Datum

Thick Surface (or Solid Datum under certain conditions)

Close Close (or Solid Datum under certain conditions)
Project Solid Datum
Volume Solid Datum
Constant Edge Fillet Edge Fillet
Constant Edge Fillet (several edges, distinct values) Variable Angle Fillet
Rolling Edge Fillet Edge Fillet (option Keep edge on)
Face-Face Fillet Face-Face Fillet
Variable Angle Fillet Variable Angle Fillet
Tritangent Fillet Tritangent Fillet
Import (with MML link) Solid Datum
Macro Primitive Copy with Link of a Body
Not Supported Primitive Solid Datum (if the solid is smart)


When migrating CATIA V4 tritangent fillets, resulting tritangent fillet shapes may slightly differ in CATIA V5. This is due to the use of different geometrical definitions.

  • In V4, a tritangent fillet is based on two variable spheres.
  • In V5, a tritangent fillet is based only on a variable tritangent circle.

This slight difference of shapes can be increased if the faces to be filleted are not normal to the face that will be removed during the filleting process. The example below illustrates it thru a solid including an important draft angle. However, despite the difference with a tritangent fillet that would be created directly in V5, the whole volume remains the same.