Morph Constraints Panel

This option works in conjunction with the equal to /upper bound / lower bound switch and calculate button.

Clicking twice on the label/button opens the calculator.

at origin

Use the origin point of the default global system.

at node

Select the desired node.

at system

Select the desired local coordinate system.

This option works in conjunction with the equal to /upper bound / lower bound switch, calculate button, and find center / center axis / center line / center node switch.

Clicking twice on the arc angle label/button opens the calculator.

This option works in conjunction with the equal to /upper bound / lower bound switch, calculate button, and elems selector.

Clicking twice on the area label/button opens the calculator.

continuous, main-secondary, attached tangency

Select two domains to be constrained; one for each domain selector.

Note: Continuous is the only tangency type available for 2D domains.

fixed end tangency

Select an edge domain to be constrained; select a node at the end which is to be constrained and a vector to orient the end of the edge domain.

equal to

Do not change the node list's overall length.

upper bound

Contract the node list, but do not expand beyond the specified length.

lower bound

Expand the node list, but do not contract to less than the specified length.

In the dialog that opens there are two collectors which match the contents of the nodes and elements in the panel. You can modify the selected nodes and elements by double-clicking these collectors.

The dialog also contains an entry field which you can use to enter the number of model units or number of element rows. After the entry field there is a selector which you can use switch between model units and element rows.

If model units is selected, any nodes beyond the given number of model units will be excluded from the selected nodes. If element rows is selected, any nodes beyond the given number of element rows away from the selected elements will be excluded from the selected nodes. For element rows, the rows of elements must be attached to the selected elements and all nodes not a part of the rows of elements will be excluded.

When exclude is clicked, any nodes beyond the given criteria are removed from the selected nodes. If no nodes have been selected, all the nodes in the model which are not attached to the selected nodes are placed on the mark and those beyond the given criteria are then excluded from the mark.

Figure 3 shows how the exclude beyond functionality is used. In the image on the left, all of the nodes for the crimson mesh and the elements shown in gray are selected for an on elements type morph constraint. Using the exclude beyond dialog, model units is selected as the distance option and a distance of 1000.0 is used to exclude all of the nodes which are more than a thousand model units away from the selected elements. In the image on the right, the exclude has been clicked and the nodes left on the mark are those at or within one thousand model units of the selected elements.

Figure 3.

find center

Infers the center from the plane of the edge domain.

center axis

Use a plane and vector selector to specify a plane and base node. The axis is the plane's normal at the base node.

center line

Specify the desired line.

center node

Specify the desired node.

Replace constants a, b, c, r, and R with numbers. For more complex shapes defined by more than one equation (such as a torus) the corresponding equations fill into each of the two text fields.

You can also specify your own function. The function may contain x, y, and z variables with the rest being numbers or expressions. The surface defined when the function is set to zero will be used as the boundary for the constraint. You can add more equations by means of the prev and next buttons.

x translation (r)

Fix the x or r coordinate of each node with respect to the coordinate system.

y translation (theta)

Fix the y or theta coordinate of each node with respect to the coordinate system.

z translation (phi)

Fix the z or phi coordinate of each node with respect to the coordinate system.

fully fixed

Translate and rotate the inner nodes to match changes in the constraint elements, preserving the initial distance and orientation.

translate only

Translate the inner nodes to match changes in the constraint elements, preserving the initial distance.

force normal

Force the inner nodes to lie normal to the constraint elements when the constraint is created.

allow sliding

Move the inner nodes perpendicular to the normal direction as long as the initial distance in the normal direction is preserved.

Clicking twice on the length label/button opens the calculator.

This value is calculated based on the area/volume of the selected elems, and density data supplied by a property card. The total mass remains fixed after morphing, even if the shape of the element cluster changes.

Clicking twice on the mass label/button opens the calculator.

node list

Use the node list already specified under the length switch.

N1N2

Select two nodes in the mesh. The length is measured along the line between them.

x axis, y-axis, z-axis

Measure the length along the chosen axis of the default global coordinate system.

moves along

Define an entity, vector, or equation along which the nodes are permitted to move during a morph operation.

You can constrain nodes to move along a vector, line, plane, surface, elements, or an equation. These nodes will follow the feature selected during morphing enabling you to alter the shape of a mesh while keeping it on a line, surface, vector, plane, mesh, or surface of a function. The nodes constrained to a feature do not need to be on the feature to begin with, but they will be moved to that feature when the constraint is applied. You may also constrain a node where a handle is located and that handle will follow the constraints. You can have as many constraints as you desire per node, but if conflicting constraints exist, there is no guarantee that any of them will be satisfied.

Figure 4 shows nodes constrained to a line. The marked nodes are constrained to follow the highlighted line. When the rightmost handle is moved to the end of the line, the constrained nodes move along the line while the unconstrained nodes are unaffected. However, if mesh stretching is applied the unconstrained nodes will stretch to match the perturbations of the constrained nodes resulting in a smoother mesh. Additionally, placing handles at constrained nodes can be used to achieve mesh stretching.

Note: The handle nodes were also constrained to the line. This means that when perturbations are applied to the handle, the handle will be mapped back onto the line to preserve the constraint condition.

Figure 4.

bounded

Define a location past which the nodes will not travel, and to specify a minimum distance to maintain from this boundary (in which case they will approach, but not reach, the boundary).

You can constrain nodes to vectors, lines, planes, surfaces, and elements.

Figure 5 show nodes bounded by a line with a set distance beyond which the nodes cannot move. In the first case (top two pictures), the mesh does not stretch to accommodate the constraint. However in the second case (lower two pictures), creating handles at the constrained nodes (and making them dependent on the handles which are being moved) allows them to move along with the perturbed handles and affect the mesh when they encounter a constraint. A similar effect can be achieved by applying the mesh stretching option, but by using handles the user can control the amount of stretching by adjusting the handle biasing factor.

Figure 5.

set distance

Specify a minimum distance to maintain from this boundary or maintain the constrained nodes at their current distance from the bounding plane during morphing operations.

fixed layers

Position multiple layers of nodes at the initial distance they were from the target elements.

Compared to the set distance option, fixed layers is faster and has some more powerful features. This option was developed specifically for CFD meshes where thin boundary layers of matching nodes are commonly used.

abv plane

Angle is determined normal to the plane defined by the node a, vertex, and node b selected above.

N1N2

Select two nodes in the mesh. The angle is defined normal to the line that they define.

x-axis, y axis, or z-axis

Angle is measured normal to the global axis that you choose.

To update an existing constraint, either enter its name, or click the button twice and select the desired constraint.

This option works in conjunction with the equal to /upper bound / lower bound switch and calculate button. The radius is measured using an edge domain and one of the following methods for finding the center of curvature: an axis, a line, a node, or inferred from the plane of the edge domain.

Clicking twice on the radius label/button opens the calculator.

smooth nodes

Apply to the nodes directly,

smooth dep. handles

Apply to dependent handles between the morphed handles.

This option works in conjunction with the equal to / upper bound / lower bound switch, calculate button, and elems selector.

Clicking twice on the volume label/button opens the calculator.

Click Apply to reapply the constraint (which will apply all active constraints) or perform another morphing operation.