Components in the Design and STEP Models
Manufacturers often provide STEP models for their parts. These models can be downloaded, gathered into folders and associated with Pulsonix footprints. The models can be viewed using the Library Manager - STEP Models page.
Adding Component Attributes for STEP Model usage
To use STEP models within your PCB design, add the attribute STEP Filename to the Footprint in the footprint library, or to the Part definition in the Parts library or it can be added directly to the component in the PCB design. For footprints, the attribute can also be added using the Position STEP Model dialog. It is normal to add this to the footprint but could be added to the Part definition if you prefer. If using multiple footprint definitions on a Part, you would not add it to the Part but add the attribute to each footprint so that the correct model is used.
STEP Filename Usage Precedence - If the STEP Filename attribute is assigned to both the Footprint and the Part definition using it, the attribute precedence is determined by whether Footprint or Part is selected in Design Settings | General | STEP Model Alignment. Depending on the selection, either the Footprint or the Part attribute will take precedence in the 3D Viewer and STEP output file.
It is recommended that the value of the attribute should match the filename of the STEP model. This way, at the association stage, it is easier to pair the footprint name to the STEP model name.
In order of presidence, when running the 3D Viewer, if this attribute is not set up, or is not found, the 3D Package will be used. If this is not available, then the Component Height attribute will be used, if this is not available, then a simple box following the component bounding box is output with a built-in height of 2mm.
Component Height attributes can be extracted automatically from STEP models used in the design using the Generate Heights From STEP option from the Utilities menu.
To override the STEP model name to use your own 3D Package, simply omit the STEP Filename attribute from the footprint or part. The normal 3D Package name to footprint name match rules then apply.
By adding the STEP Filename attribute but leaving it’s value blank, you can completely suppress the output of any graphical 3D model information; STEP model or 3D View package.
The STEP Filename attribute can also be added to PCB Documentation Symbols so that they can use STEP models. The STEP Offsets and STEP Rotation attributes work in the same way for these symbols.
To make the process easier, the STEP Filename, Offsets and Rotation attributes can be added graphically to a Footprint or PCB Doc Symbol by using the Position STEP Model dialog which is available in their respective Symbol Editors.
Suppressing Models
If the intention is to prevent any 3D image being rendered for a particular component or footprint, this can be achieved by adding the <STEP Filename> attribute but leaving its value blank. Alternatively, if you wish to explicitly always leave the STEP model suppressed, you can add the <STEP Suppress> Attribute to a component. This will suppress it for the 3D Viewer and output file.
Positioning the STEP Model
When positioning the STEP model in the Z-axis, the application will by default assume that the model is defined with Z=0 on the seating plane of the component. If this is not the case, you can apply an adjustment in the Z-direction by adding the STEP Offsets attribute to your component. Supply the distance in mm by which the model should be offset in the Z-direction to bring the seating plane in line with the board surface. The adjustment value is added to the current board Z-coordinate, so a negative adjustment will decrease the Z position and hence move the component downwards toward the board surface. You can also make adjustments in the X and Y axes. To make multiple offsets in different axes the attribute value takes the form of X=1.02;Y=5.3;Z=2.0. if you do not want an offset in an axis just omit it. The default units are millimetres. If you omit the axis letter then Z is assumed.
Similarly, if you want to apply a rotation in any axis use the STEP Rotation attribute. This uses a similar notation as the offset attribute. X=90.0 will rotate the model in the X axis. If you omit the axis letter then X is assumed. For example, it could look like this for the STEP Rotation attribute field: <STEP Rotation> X=90;Y=180;Z=0
When defining the <STEP Rotation> or the <STEP Offset> attributes, use the ; (semicolon) character for value separation. The character used for this feature is fixed in Pulsonix and cannot be changed.
Model Placement Areas
The orientation of the component STEP model and the footprint may be different. You can add a Model Placement area to the footprint to aid matching them up. The application will use the relative height/width of this area to compare with the height/width of the component to decide whether the model needs to be rotated or not. You can preview the model when adding the Placement Area to check the footprint alignment with the model. Use the View STEP option from the View menu. If the model filename attribute has not been defined, a warning message will be displayed.
No Transformation switch on the Design Settings dialog
From within the Design Settings, General dialog, there are switches to set the STEP Model Alignment.
Related Topics
STEP Overview | STEP Models | STEP Model Folders | STEP Model Library | 3D Settings | Model Placement area | STEP Import Positional Changes | Import STEP Board | Generate Heights From STEP | Outputting STEP Files