Groups and bodies
A document consists of an ordered list of groups. Each group contains entities and constraints that result in a set of equations that gets solved. Groups are solved in the order they’re in the document. Once a group is solved, the position of its entities can’t be modified by subsequent groups.
Groups can optionally have an active workplane. It can be in the same of any previous group. Use the “Set workplane” and “Clear workplane” tools to change the active workplane. With an active workplane, it becomes possible to draw entities in 2D space in that workplane.
Groups can be reordered with the restriction that a group and its entities and constraints must only reference the group itself or previous groups.
Deleting a group will also delete all dependent groups and entities.
Bodies break up the solid model, in the way that the first group in a new body isn’t aware of the solid model of the preceding body. Bodies have no effect on entities and constraints and can be created and removed without adverse effects. That way, bodies are useful to create parts consisting of multiple sub-parts such a box with a lid. To add a body, select the checkbox next to “Body” in the Group tab or click on “Sketch in new Body” in the plus menu below the list of groups.
Bodies can optionally have a solid model color assigned to them. By default, it is set by the color theme. To make it easier to tell bodies apart, their solid model color can be overridden. To do so, select the checkbox next to the color button in the first group of the body or use the context menu of the body’s row in the workspace browser. The solid model color is saved in the document and not part of the workspace view state unlike solid model visibility.
Reference
A reference group is the first group in any document. It automatically contains three workplanes, one for each axis. Neither the group nor its workplanes can be deleted. Reference groups can’t be added explicitly. Pressing delete on a reference workplane hides it. I can be made visible in the group settings of the reference group.
It’s not possible to add entities to the reference group or to set an active workplane.
Sketch
A sketch group is meant for adding entities either in a set workplane or in 3D.
The solid model operation of a sketch group applies to STEP model entities that are part of the solid model.
Extrude
An extrusion group extrudes closed paths from the source group’s active workplane along the extrusion vector. When creating an extrusion group, the current group and its workplane become the source of the extrusion group. The workplane reference is stored in the extrusion group, so changing the active workplane of the source group has no effect. To create an extrusion group, the current group must have an active workplane.
If the “along normal” switch is on, the extrusion vector is along the source workplane’s normal and the group has one degree of freedom instead of three.
Setting the mode to offset adds one extra degree of freedom to change the start of the extrusion to an arbitrary point along the extrusion vector.
If there is no preceding solid model in the current body, the operation (union or difference) has no effect.
It’s possible and supported to create multiple disjoint solids in one extrusion group.
An extrusion group adds lines parallel to the extrusion vector for every point in the source group and the origin of the source workplane. It also adds translated copies of entities from the source group that formed the profile of the extrusion at the faces of the extruded solid.
Lathe
A lathe group creates a solid by rotating closed paths from the source group’s active workplane along a specified point and vector. The workplane reference is stored in the group, so changing the active workplane of the source group has no effect. To specify the lathe axis, either a line or a workplane must be selected when creating the group. If a workplane is selected, lathe group is based on its normal vector.
For proper solid model generation, the paths should not cross over the vector, as otherwise the body will self-intersect and cancel itself out.
A lathe group adds no degrees of freedom.
For every point in the source group, it adds a circle centered and oriented to the lathe axis that passes through the point.
Operation has the the same semantics as in extrusion groups.
Revolve
Similar to a lathe group, a revolve group also rotates closed paths from the source group along a specified point and vector. It differs from a lathe group in the way that it only sweeps the paths by a variable angle. It thus adds one degree of freedom. Setting the mode to Offset makes the start angle another degree of freedom.
Similar to an extrusion group, a revolve group translates its source entities to the faces of the revolved solid. Unlike lathe or extrusion groups, it does not create entities from points in the source group.
Since version 1.2
Loft
A loft group creates a solid by interpolating between closed paths from two or more sketches. It adds no degrees of freedom or entities and requires each source group to contain exactly one closed path in its active workplane.
Since version 1.2
Linear array
A linear array group replicates entities from its source group as often as specified in “Count” along a vector. Its detailed operation depends on whether it has an active workplane or not. If the source group has no generated entities like loft, there will be no entities in the linear array group to constrain the translation increment. To work around this, manually add entities to the source group.
If the array group has an active workplane, the vector is in that workplane so it adds two degrees of freedom. Entities from the source group in the same workplane will be copied, as well as entities in 3D space. Entities in other workplanes won’t be copied.
If it has no active workplane, the vector is in 3D space so it adds three degrees of freedom. Only entities in 3D space will be copied from the source group.
Setting the offset to “original” places the first copy at the same location as the entities from the source group.
Setting the offset to “first copy” places the first copy one vector away from the original.
Setting the offset to “arbitrary” places the first copy at an arbitrary point, adding two or three degrees of freedom.
If the source group has a solid model, its operation is repeated for each instance of the array.
Since version 1.4, multiple source groups are supported. The array operation is repeated for all source groups. Solid models are first accumulated using each source group’s solid model operation to make up the array group’s solid model and then applied to the body using the array group’s solid model operation. This means that the solid model operation of the first group has no effect. A limitation of this implementation is that it’s not possible to use multiple source groups that add and subtract from the accumulated solid model.
Polar array
A polar array group replicates entities from its source group as often as specified in “Count” in circular fashion centered around a point. A polar array group always requires a workplane to specify the plane of rotation. To create a polar array group, select a workplane first.
By default, it adds three degrees of freedom: Two for the center point position, one for the angular increment.
Offset, handling of the solid model and multiple source groups work just like in the linear array group.
Fillet / Chamfer
Unlike the other groups, these only operate on the body’s solid model and don’t create any entities. Use the “select edges” tool to select the edges the fillet/chamfer is applied to.
Unlike everywhere else, these edges are references to features in the solid model and thus are subject to the topological naming problem. Therefore, it’s recommended to apply these operations as the last step in the document’s modelling sequence.
Warning
Chamfers and Fillets created with version 1.1 or earlier (this commit to be precise) may appear on the wrong edge starting with version 1.2.
Exploded cluster
This group can only be created from a cluster with the “Explode cluster” tool. It contains the entities and constraint from that cluster in the cluster’s workplane so they can be edited. To put them back into the cluster, use the “Unexplode cluster” tool, also available from the group tab.
Since version 1.2
Mirror Horizontal / Vertical
A mirror group mirrors entities across the horizontal or vertical axis of its workplane. A mirror group therefore must always have an active workplane. In-workplane entities will only get mirrored if they’re in the group’s workplane. Entities in 3D space and the solid model will get mirrored across a plane defined by the horizontal/vertical axis of the workplane and its normal vector.
The “Include source” switch defines whether or not the source entities should be present as-is in the mirror group. This is intended to be used to make symmetric extrusions and the like.
Solid model handling is identical to array groups.
Since version 1.3
Solid model operation
A solid model operation group performs a solid model operation (that is: union/difference/intersection) between two solid models of arbitrary groups. Unlike all other groups that generate a solid model, it’s not bound to the standard modeling sequence that only considers the previous group’s solid model. It’s therefore possible to perform operations on the solid models from two otherwise independent bodies.
This group adds no entities or degrees of freedom.
Since version 1.3
Clone
A clone group copies all entities from the source group’s active workplane into its own active workplane. A clone group must therefore always have an active workplane. When creating a clone group, the current group and its workplane become the source of the clone group. The workplane reference is stored in the clone group, so changing the active workplane of the source group has no effect. To create a clone group, the current group must have an active workplane.
It’s intended use case is reusing paths for extrude groups in another place or orientation.
This group adds no degrees of freedom.
Since version 1.3
Pipe
A pipe group extrudes closed paths from its source group along one or more spine entities. The selected spine entities must form a path, i.e. have coinciding end points. Supported spine entities are:
Line in workplane
Arc in workplane
Bezier curve in workplane
While all spine entities must be in a workplane, they can still be in different workplanes to each other, making it possible to create solid models that look like this:
To select spine entities, use the so-called tool or click on the button next to Spine in the Group tab.
For proper solid model generation, it can be required to set a start point. A start point can be set clicking on a point that’s part of a spine entity in the “Select spine entities” tool.
This group adds no entities or degrees of freedom.
Since version 1.3