Using Transforms

Displayers use transforms to modify the default position, orientation, or size of the part in the displayer.

Located in the Tools > Transforms node, transforms can repeat or mirror parts, or reposition, resize, or reorient them. The transform feature is for viewing only.

In Simcenter STAR-CCM+, a transform is used with a displayer to allow for the repositioning, reflection, or repeat of parts in a scene. Transforms also work with coordinate systems (the Laboratory coordinate system by default).

A new simulation contains one transform named Identity, which cannot be deleted or renamed. You can create additional transforms directly through the pop-up menu.

A transform can be applied to a displayer to view the entire model for a solution in which only a symmetric or periodic repeating portion was solved. For example, when modeling a compressor stage, often you only solve for a single blade row. It becomes useful to view adjacent blade rows, or even the entire repeating solution. Using a periodic transform as the displayer’s transform provides a way to view the complete geometry. Similar arguments apply for a problem with mirror symmetry.

A simple transform can be used in a displayer to view parts which would normally occlude each other by separating them.

All transforms can be renamed, except for the identity transform. All transforms can be copied provided they are of the same type.

Note	When you switch the coordinate system of a transform, you change the spatial position of that transform. To compensate for this change, adjust spatial properties (such as Rotation Axis and Rotation Origin) of the transform. For details, see How Transforms Work with Coordinate Systems.

Simcenter STAR-CCM+ provides the following types of transforms:

Automatically Generated Transforms

Periodic Repeat

This transform is automatically generated from a periodic interface once you initialize the solution, and is deleted if the interface is deleted. This transform gets most of its values automatically from the interface, such as the rotation angle, axis of rotation and translation vector, so the only property you can change is the number of repeats (copies). The graphics periodic transform lets you edit everything, but you must set all of its properties from scratch.

Applying a periodic transform to a displayer shows the specified number of copies of the parts in the displayer, at periodic intervals based on information from the interface. Hence, the portion of the device that gets displayed depends on the following:

The parts included in the displayer
The number of copies
The intervals between the copies

Symmetry

This is an automatically generated transform from a symmetry boundary. This transform automatically extracts the plane of symmetry from the boundary. This transform is tied to the boundary and hence cannot be edited, and is deleted if the boundary type is changed, or the boundary is deleted. Applying a symmetry transform to a displayer shows the mirror image of the parts in the displayer about the symmetry plane.

Axisymmetric Embedding or Blade Embedding

This transform is automatically added when you create a parameterization (axisymmetric or blade). It is available for creating a 2D projection of a 3D surface, for example an isosurface along a turbine. See Applying Parameteric Coordinates.

You can create this type of transform manually, but then you must map it to the appropriate parameterization by making a selection in the Parameterization property.

When you use this type of transform in a vector displayer, the projection mode is always tangential, that is, projecting the vectors with the tangential component. While you can still set the projection mode in the displayer properties, the setting has no effect on this transform. When you switch to another transform, the vector displayer reverts to whatever projection mode is currently selected.

When you select this type of transform, the view in the scene automatically changes so that you are looking down the z-axis at the embedded transform. Switching between conformal and isometric embedding types in the transform has the same effect.

Identity

This transform is the default transform for all displayers. There are no properties associated with this transform, and when applied to a displayer, shows all parts in the displayer at their natural position, size, and orientation.

User-Defined Transforms

Simple Transform: This transform does not copy the original part, but translates, rotates, or scales the part accordingly. Applying a simple transform to a displayer transforms the parts in the displayer accordingly.
Graphics Symmetry Transform: This transform behaves the same as a symmetric transform, but it is your responsibility to define the plane of symmetry. The plane is of the form ax + by + cz + d = 0, where a, b, and c are the x, y, and z components of the plane normal and d = -ax0 - by0 -cz0 where x0, y0, and z0 are the origin of the plane.; For an axisymmetric problem, the axis is always the x-axis. Therefore you should enter 0,1,0,0 in the Plane property of this transform.
Graphics Periodic Repeat: This transform behaves the same as a periodic transform, but it is your responsibility to define the rotation angle, rotation axis, or translation vector.
Meridional Projection Transform: This transform is a simple projection of the points of the part into the (z,r) plane.
Motion Transform: This transform updates the displayer position according to the displacement of the chosen motion in each time-step. If you activate Use Inverse, the inverse displacement of the chosen motion is applied. In this way, if a part is already moving according to the chosen motion, and you wish to have a static view of the part, you can apply the inverse motion to the displayer. Alternatively, if you wish otherwise static parts to move alongside a moving part, you can add the static parts to a separate displayer and assign the motion transform to that displayer. Only rigid motions, such as translations and rotations, can be used.; Switching between motions updates the transform. Alterations to the motions affect the transforms. For example, a motion that rotates during a simulation updates the transform as the simulation progresses. Updating a motion does not immediately cause a new rendering to occur. This means that a scene will not be rerendered during a time-step. Instead, as usual, the rendering occurs after the time-step with the updated motion information. No effect on solvers has been observed.; For DFBI, a 6-DOF body motion can be used. Once a DFBI body is created, the context menu of that body includes a command to create a 6-DOF body motion that is tied to one DFBI body.