Once the MCAD model has been placed near the component footprint, it can be positioned. It is common that a 3D MCAD model will need to be reoriented to suit the footprint.
There are a number of tools and features to help with this process.
Generally, it is easy to perform rotation tasks in 3D display mode, and X-Y positioning tasks, such as aligning a Snap Point with a location on the footprint, in 2D display mode.
Reference Point and Snap Points
Reference and Snap Points provide a way of holding a 3D Body object during placement. If the Snap to Center option is enabled in the PCB Editor – General page of the Preferences dialog, the cursor will automatically snap to the nearest vertex/reference point/snap point when you click and hold to move the object.
Generic models will have a reference point assigned in the MCAD software in which they were designed.
Snap points are user-defined locations, which allow the object to be held at that location as it is moved in the design space. Snap points are typically assigned to an edge or corner of the object or a center location, for example, the center of a pin or mounting peg.
Snap points can be added by entering the X, Y & Z locations in the Snap Points region of the Properties panel or they can be added interactively using the Add Snap Points From Vertices command. It is easier to interactively add Snap points in 3D mode.
To add snap points:
Press 3 to switch to 3D layout mode.
Select the Tools » 3D Body Placement » Add Snap Points From Vertices command.
As shown on the Status bar, the next step is to Pick the STEP model to add snap points to; click to select the required 3D Body object.
The Add Snap Points From Vertices command has two modes (use the Spacebar to toggle between the modes):
Click on a single vertex to add a snap point at that location, or
Click on two separate vertices; the snap point is added midway between them. Use this technique to add a snap point to the middle of a component pin.
Press the Spacebar to select the required mode.
Click a vertex to define the snap point location.
If the two-click mode is being used, click a second vertex to define the second location; the snap point will be created midway between the two click locations.
Continue placing snap points or right-click or press Esc to terminate the command.
Visibility controls for the 3D Body Reference Point and Custom Snap Points are located in the System Colors region of the View Configuration panel.
Orienting a Model in the Properties Panel
An excellent approach to orienting a model is to use the 3D Body mode of the Properties panel. Because the values can be edited from the keyboard, it is easy to quickly test various X, Y or Z values and change the orientation as you observe the model in 3D. The keyboard can be used to:
Ctrl+F – to Flip the view over.
M – to move an object.
J – to Jump to a location in the design space.
R – to select Reference (the PCB library editor design space origin) from the Jump sub-menu.
Enter – to apply the value just typed into the panel and also to place the model being moved.
This can be used to rotate the model around each axis, and raise or lower it in the Z plane (demonstrated in the video below).
The Properties panel can be used to visually reorient the model.
Using the Orientation Commands
The software includes commands for orienting and positioning a component. It requires the designer to select three snap points that lie on the surface of the PCB then indicate the three reference points on the PCB to which each of these snap points should be mated. The process is described below.
To position and align a model to a footprint:
Switch to 3D Layout Mode (3 shortcut).
Run the Tools » 3D Body Placement » Orient and Position 3D Body command.
The Status bar will prompt you to select a model; click the generic model you want to reposition.
Three anchors must now be selected, one after the other. Ideally, these will be an accurate reference, such as a pre-defined model reference point, or a snap point located at the center of a pin. The Status bar will indicate which anchor you are currently up to. Note that the Status bar displays a numerical reference value for the vertex or snap point that is currently under the cursor – user-define Snap Points have a low value, from 2 upward; keep an eye on this value to help identify the correct click location. Refer to the Defining Snap Points section to learn more about adding Snap Points.
Once the three anchors have been chosen, the next step is to select, in the same order, the three locations on the footprint where these anchors are to sit. Use the Status bar to guide you as you select the three locations. Note that the cursor will be blue as you move it through the design space, but will change to green if you are over the center of an object, such as a pad.
As soon as the third anchor location has been clicked on, the model will change its orientation and position as the software attempts to mate these three locations. The command will then terminate.
This process is demonstrated in the video below.
Video demonstrating the process of re-orienting a Generic Model.
Center Snapping for 3D models
To improve the convenience and accuracy of adding Snap Points to a 3D model, the following points are automatically snapped to, during Snap Point definition:
All hole centers.
The 90° locations (points crossing the orthogonal axes) around a hole circle.
The middle of a border line.
The model’s body axis.
The center point in a line between two snap points (Spacebar mode).
These snap points were added using the automatic snap to hole center capability.
Snapping to these locations is also available when using the Reports » Measure Distances command in 3D Layout Mode.
Browsing 3D Bodies using the PCB - 3D Models Panel
In the PCB panel’s3D Models mode, its three main regions change to reflect the 3D bodies hierarchy of the current PCB design (in order from the top):
Specific Components associated with the component class that have associated 3D body object(s) or free models (non-PCB mounted, free-floating 3D bodies)
The individual 3D bodies for each component or free Models
Double-click a component entry in the Components region of the panel (or right-click then choose Properties) to open the Component mode of the Properties panel where you can edit its properties in detail. Similarly, double-click a model entry in the Models region of the panel (or right-click then choose Properties) to open the 3D Body mode of the Properties panel in which you can edit the complete 3D body properties.
The PCB panel can be used to select display properties for 3D models. The icons represent different levels of transparency from 100% (hidden) down to 0% (solid) in increments of 25%. You can select multiple components and apply the same display controls to them at once using the Highlighted Models options.
The icon may be used to enable or disable Design Rule Checking of 3D object types that contain a STEP model. The icon may be clicked once to uncheck (or disable) the feature, or clicked twice to check (or enable) the feature.
The selected model being set to 75% Opacity. Multiple models can also be selected and changed in one step.