By adding tangency conditions you can pull the surface of the loft in the direction of the tangent. For profile lofting you define the tangent conditions beforehand with Add Tangent in Basic Loft.
Unless you switch AutoWeight on, tangency conditions are always valid for the complete profile, workplane, or face. With AutoWeight on, Creo Elements/Direct Modeling tries to optimize the tangent conditions and applies a varying tangent weight for all specified tangents. The tangent directions do not vary.
You can add tangency conditions to
• Workplanes.
• Profile elements.
• Vertices on profiles.
The following figure shows a profile loft with no tangent and a loft with a profile element tangent of -45 degrees.
To add a tangent for a profile loft,
1. Click Modeling and then, in the Model group, click More.
2. Click Add Tan in Basic Loft section.
3. Specify a workplane set to add the tangent to using one of the following ways:
◦ Click the workplane set from the Browser and click Apply.
◦ Click the border of a workplane in the set.
◦ Enter the name of the workplane set.
4. You now have three choices:
◦ Add a tangent to a workplane:
1. Click Workplane and specify the workplane. Use one of the following ways:
a. Click the workplane from the Browser and click Apply.
b. Click the border of the workplane.
c. Enter the name of the workplane.
2. Specify the direction for the tangent. Click Direction and use the options in the Direction 3D menu.
3. Specify a weight (between 0.2 and 5 - the greater the number, the stronger the pull of the tangent) for the tangent using one of the following ways:
a. Enter the weight in the data entry field next to Weight.
b. Click Weight and enter a weight.
4. Click Apply to add the tangent without ending the operation.
◦ Add a tangent to an element of a profile:
1. Click Profile and click the profile element.
2. Click Angle and enter the angle for the tangent. (The angle direction depends on the direction of the matchline.)
3. Specify a weight (between 0.2 and 5 - the greater the number, the stronger the pull of the tangent) for the tangent using one of the following ways:
a. Enter the weight in the data entry field next to Weight.
b. Click Weight and enter a weight.
4. Click Apply to add the tangent without ending the operation.
◦ Add a tangent to a vertex of the profile:
1. Click Vertex and specify the vertex.
2. Specify the direction for the tangent. Click Direction and use the options in the Direction 3D menu.
3. Specify a weight (between 0.2 and 5 - the greater the number, the stronger the pull of the tangent) for the tangent using one of the following ways:
a. Enter the weight in the data entry field next to Weight.
b. Click Weight and enter a weight.
4. Click Apply to add the tangent without ending the operation.
5. Click AutoWeight on. Creo Elements/Direct Modeling will optimize the tangent conditions by varying the specified tangent weights.
6. Continue adding tangency conditions or click to complete the operation. The resulting shape of the freeform part with tangencies applied depends on the direction of the matchline. This behavior is similar to adding tangents to splines in 2D geometry.