About Propagating Tangency Using Move, Offset, and Modify Analytic Tools

When you modify geometry using Move, Offset, or Modify Analytic tools, you can maintain the tangency between the modified and the neighboring geometry. You can maintain existing tangency, but you cannot create tangency.

The geometry that is moved, offset, or modified is called transformed geometry, whch is the geometry you select. To maintain the tangency, the geometry selection may automatically expand to neighboring entities based on their tangency to the selected entities. The geometry that is automatically added to your selection in order to maintain tangency is called dragged geometry.

While modifying or creating geometry, the surfaces and edges of the model are shown in different colors. The colors are based on the tangency of the geometry in relation to the transformed geometry:

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—Transformed geometry. The primary reference surfaces for the Move, Offset, or Modify Analytic tools.

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—Dragged geometry. These surfaces are not directly transformed, but they are tangent to the transformed geometry or to surfaces that are tangent to the transformed geometry. They are solved by the system to maintain tangency.

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—Rounds that can be propagated. Tangency propagation can be forced to be carried through and continue to the adjacent tangent geometry. The surfaces connect transformed or dragged geometry to the background geometry and are analytic (cylinder or torus). These rounds are removed and recreated. If a condition other than Fixed is added, they become dragged geometry, and the system solves their position and attributes (for example, radius).

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—Rounds that cannot be propagated. The tangency stops and cannot be forced to go further. The surfaces connect transformed or dragged geometry to the background geometry and are not analytic. Because they are not analytic, these rounds cannot be solved. They can either be removed and recreated, or they can remain fixed by adding a Fixed condition.

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—Rounds that cannot be recreated. They are mainly variable rounds. Variable rounds can be removed but cannot be recreated because the radii and locations cannot be determined.

If a variable round is a cone, which is analytic, it can be propagated. A cone is not shown in red even though it is a variable round. Instead it is shown in light blue as a round that can be propagated. If you add conditions, it becomes dragged geometry.

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—Interfering rounds. Rounds that do not connect transformed or dragged geometry to the rest of the model but have to be removed and recreated to accommodate the changes in the transformed geometry, dragged geometry, and other rounds.

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—Fixed geometry. Rounds or dragged geometry to which a Fixed condition is added. A Fixed condition can tangency or devoid of tangency.

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—Background geometry. Geometry that is not transformed, dragged, fixed, or connecting.

The dragged geometry is analyzed to maintain existing tangency with the transformed geometry. To minimize changes to any geometry that is not dragged, tangency constraints and default fixed point conditions are created.