Transforming a CAD Model

You can transform (translate, scale, and rotate) your CAD model. Also, if desired, you can keep a copy of the original, unmodified CAD model as well as create a new coordinate system for the transformed model.

To transform your CAD model, open the CAD Transform dialog box (Operation | Graphic Display Window | Transform). Use the items in the dialog box as needed, and then click OK or Apply.

Performing a CAD transform operation does not transform any existing learned features. This operation essentially renders them useless. You may want to perform a File | Save As operation to create a backup of your measurement routine and CAD model before you proceed.

CAD Transform dialog box

CAD Transform dialog box

Keep original - This check box lets you keep a copy of the original, unmodified CAD model.

Create new coordinate system - This check box lets you create a new coordinate system from the newly-translated CAD model. For more information, see "Working with CAD Coordinate Systems".

Translate - This area defines the XYZ offsets to translate the model. You can type the specific location to which you want PC-DMIS to move the coordinate system. If you do not know the coordinates, you can use the Select button to select a specific CAD entity to which the coordinate system moves. See "Transforming by Selecting" below.

Scale - This area defines how the CAD model is scaled. This can be useful for fixing models that are not scaled correctly due to improper measurement-unit identification. For example, if the model is sized for millimeter units but you want it scaled for inch units, you can scale the model by 25.4.

The Uniform check box uniformly scales the model. If you want to scale a selected axis of the model, clear the Uniform check box. Leave the value as 1 for axes that you do not want scaled, and change the axis that you want scaled. You can also scale axes by negative values. This is useful if you want to mirror an axis. In this case, enter -1 for that axis.

Mirror - In this section, you can mirror the CAD view of a part. Mirroring provides the same functionality as using Scale with -1 specified for the mirroring axis. Mirroring your CAD model is particularly useful when measuring automotive parts that have identical left- and right-hand pieces. If CAD information is available for the right side of a part, you can mirror the appropriate axis, and create a CAD view of the left side of the part.

The Mirror option does not create a new measurement routine in the mirrored image. If you want to mirror your measurement routine instead, see the "Mirror" topic in the "Using Basic File Options" chapter, and follow the instructions.

To mirror the CAD data, do the following:

    1. Select the axis you want to mirror. If you want to keep your old CAD data so that after mirroring you have CAD data for both the symmetrical halves, select the Keep original check box.

    2. Click Apply or OK. PC-DMIS mirrors the CAD drawing in the specified axis and displays the image in the Graphic Display window.

Mirrored Elements in CAD Assemblies

If you open the CAD Assembly dialog box, you can see that your original imported image name has the number 1 appended to its name. Any CAD transformation that creates a new instance of the same CAD file (such as a mirror operation) is then incremented to have a unique number. See "Working with Assemblies of Parts".

Mirrored CAD file names with unique numbers inside a CAD Assembly Tree View

Hidden Assembly Components During a Mirror Operation

If you hide elements of your CAD assembly prior to mirroring your CAD data, hidden components are still mirrored, but their mirrored counterparts also continue to remain hidden in the Graphic Display window until their visibility state is modified in the Assembly Tree View of the CAD Assembly dialog box.

Rotate - This area controls how the CAD model is rotated. Type the angle you want to rotate the model by in the Angle box. You can type the specific location to which you want PC-DMIS to move the coordinate system. If you do not know the coordinates, you can use the Select button to select a specific CAD entity to which the coordinate system moves. See "Transforming by Selecting" below.

Rotate axis - This area defines the line about which the CAD model is rotated. The model rotates about this line by the specified angle. The direction of rotation follows the right-hand rule. You can use one of the coordinate-system axes as the line to rotate about by selecting the appropriate X, Y, or Z axis option button. If you do not want to rotate about one of the coordinate system axes, you can rotate about an arbitrary line by selecting the Line option button. This enables the Line vector and Line point areas. Fill these areas out to determine the point and vector that comprise the arbitrary line.

Rotate matrix - As you determine your CAD model's new transformation, this area automatically gets filled out with the values to use in a 3 X 3 matrix. This 3 X 3 matrix rotates the CAD model. Usually, you won't need to fill out anything in this area as it is generally for informational purposes only.

For the Advanced User:

Transforming by Selecting

When you click the Select button, PC-DMIS displays the Select Points dialog box.

Select Points dialog box

Instead of typing an offset value, you can use this dialog box to select an offset by picking a CAD entity from the Graphic Display window.

Select point 1 - This option defines the translation location. With this option selected, click on a desired CAD entity. This anchors the point to that location.

Select point 2 - This option specifies the angle with respect to point 1 and the axis of rotation. With this option selected, click on a second CAD entity on your CAD model to define the angle.

Select line - Instead of selecting two points for your translation, this option lets you select a single line. PC-DMIS then sets the values of the Point 1 and Point 2 areas to match the start and end points of the selected line.

Reverse Points - This button switches the XYZ values of Point 1 with the XYZ values of Point 2.

Point 1 and Point 2 - These areas define the XYZ center point of the CAD entity selected with the Select point 1 and Select point 2 options. Use the check boxes in these areas to selectively update the X, Y, or Z value of the point, which enables you to specify points where there is no actual geometry for you to click on. For example, for Point 1, suppose you wanted the X and Y value of one point but the Z value of a different point. To do this, clear the Z check box and then select one point. Then clear the X, Y check boxes, select the Z check box, and select the other point.