Working with CAD objects

Starting from version 15, you can work with CAD objects in Artec Studio. You can both create CAD primitives and then export them into CAD files or import CAD objects designed in external applications. This allows you to:

• Modify and design new parts for existing objects.
• Reverse engineer scanned objects.
• Ensure quality control by comparing scanned objects to their CAD models.

Constructing CAD Primitives

CAD primitives are constructed on the basis of polygonal meshes (models) and then are fit into the latter.

Figure 131 From left to right: original object, scanned model, a set of constructed primitives.

At present it is possible to construct the following types of primitives:

• Cylinder,
• Cone/Truncated cone,
• Sphere,
• Plane.

To construct a CAD primitive, follow these steps:

1. Load a polygonal model in which you will fit the CAD primitive.

2. Open the Construct panel.

3. Select one of the available primitive types you want to construct (in the example below it is the Cylinder).

4. Choose Selection type and specify the required area on the model:

   • 2D brush or 3D brush slightly differs in how they work: the former specifies the model surface on the basis of the current viewpoint, whereas the latter works over the surface. Use the Brush size slider to change the brush size.
   • Lasso and 2D brush allows you to select the model’s backface using the Select through checkbox.

   To select an area on the model, use Ctrl+LMB above the model surface.

   

   Figure 132 Construct panel: specifying region using the 3D brush.

5. Once the required area has been selected, choose a Fitting mode:

   • Expanding is the fastest one, it allows selecting only portion of the surface where to fit the future primitive.
   • Robust is the optimal one, it is tolerant to extraneous selections.
   • Exact works exactly with the selected region.

6. Click the required primitive icon on the Primitive type bar.

7. If the selected primitive (cylinder or truncated cone) should fit into a hole of a given depth, such as a hole in a plate, then check the Smart height evaluation option. In this case, Artec Studio will use an algorithm that provides a more accurate fitting of the primitive to the model.

8. Click Fit cylinder button (or Fit sphere, etc.) to confirm your choice. Artec Studio will create a CAD primitive and fit it into the selected area.

   

   Figure 133 Cylinder (blue) fit into the model.

Use the Invert button to invert selections, and also use the Deselect button to reset all the selections you made.

See also

Importing CAD models

CAD Primitive Properties

To see the properties of the created CAD primitive, do the following:

1. Click the name or the icon of the primitive in the Workspace panel.
2. At the bottom of the Workspace panel, click the Properties section to expand it.

In the Properties section you will find the following general properties of the selected CAD object:

• Size — the size (in MB) of the object in computer’s memory
• Root mean square — the deviation between the CAD object and the model to fit into (measured as the square root of the arithmetic mean of the squared distances between them)

The presence of geometric parameters in the Properties section will depend on the type of the selected CAD primitive.

Table 18 Presence of geometric parameters in the Properties section for different CAD primitives.

Parameter	Cylinder	Truncated cone/Cone	Sphere
Radius	Yes	Yes (large and small radii)	Yes
Height	Yes	Yes	No
Angle	No	Yes	No

Positioning CAD Primitives

The Precise positioning mode benefits from the presence of parametric data in the scene. Use the Precise mode to quickly and accurately position CAD primitives, and thus scans and models to which they belong.

1. In the Workspace panel, select the models and primitives you want to align.
2. Open Editor → Precise positioning.
3. In the Primitives box, select the CAD primitive you intend to position. Below the Primitives box you will see the available positioning options (see Table 19 for details), which appear as buttons and vary with the type of the selected primitive.
4. If some other objects belong to the parent group of the selected primitive and you want to apply the same positioning actions to them, check Apply to all objects in parent groups.
5. Click either of the self-explanatory positioning buttons. Artec Studio will position the primitive in accordance with the selected option and disable this button. You will see the alignment information in the Primitives box next to the name of the selected primitive.

Every positioning action is recorded in the local history, so you can undo or redo it:

• To undo an action, use Edit → Undo or Ctrl+Z.
• To redo an action, use Edit → Redo or Ctrl+Y.

Figure 134 Editor → Precise positioning: the aligned CAD primitive is highlighted.

Table 19 Actions for primitives.

Button	Purpose	Status
Move to origin	Place the selected primitive’s point to the coordinate origin. For details, see Primitives’ Points To Use for Positioning.	O
Align with X/Y/Z	Align the primitive with the respective axis.	X, Y or Z
Align with YOZ/XOZ/XOY	Align the plane primitive with the respective coordinate plane.	YOZ, XOZ or XOY
Any	CAD primitive that you first align with any coordinate axis or plane is considered primary. A primary object will be given a priority when conflicting alignments occur.	P
Make primary	Make another object primary and remove this status from the current primary one
Reset origin	Undo the Move to origin action.
Invert direction	Invert direction of the axis or plane in the applied alignment	I
Reset alignment	Reset all the positioning actions applied to the primitive

Note

The Precise positioning tool does not affect objects with the Locked position status (). See Locking Object’s Reposition for details.

See also

Exporting CAD objects, Distance Maps and Sections and Volume.

Primitives’ Points To Use for Positioning

Depending on the type of a CAD primitive, you can use the following points in the Move to origin action.

Table 20 Primitives’ points to use in the Move to origin action.

Type of primitive	Points for positioning
Cylinder	3 points: the center of the cylinder and the intersections of the cylinder axis with its bases
Plane	The center of the plane
Sphere	The center of the sphere
Cone	3 points: the cone vertex, the middle of the cone axis, and the intersection of the axis of the cone with its base
Truncated cone	3 points: the middle of the cone axis and the intersections of the axis of the cone with its bases

To select the center of a primitive for using in the Move to origin action, click the primitive or select it in the Primitives box. The selected point and the outline of the primitive will be highlighted in white (Figure 135, left).

When you hover the cursor over the primitive’s axis, other points for positioning will appear on it. To select any of the possible positioning points, click on it. The selected point will be highlighted in white (Figure 135, right).

Figure 135 Selecting a point for positioning.

Working with Imported CAD Models

Imported CAD models can be aligned or compared with polygon models (fusion operation outputs).

Alignment

When aligning CAD models with polygon models, don’t use Nonrigid alignment and employ many point pairs (5–6 pairs). Consult Manual Rigid Alignment with Points and Specifying Points and Editing Their Positions for details.