![]() The implementation is somewhat technical, but it works. Theo Janssen’s strandbeest, model by Zolko (CC0-1.0 license) to 0, then use that variable in the Angle placement property of your part, then open the animation dialog, select the variable to animate, set min and max values to feed into the variable, as well as the increment value, and run the animation. For example, if you need to rotate a part, what you do is create a new variable and set it e.g. Internally, those are all PartDesign objects.Ī4 comes with its own tools for creating mirrored, linear, and circular arrays, as well as a measure tool:įor animation, Assembly 4 uses variables and expressions. Apart from LCS, A4 allows creating more datum types: plane, axis, and point. A large part of the feature set is about managing your assembly: creating new bodies and groups, inserting parts (there’s also a simple integration with the Fasteners workbench), mapping LCSs to each other etc. ![]() Features īecause of how the workflow is implemented, Assembly 4 doesn’t have rows and rows of buttons to go through when you need to align one part with another. We do need to point out though that with the bottom-up approach, it is impossible to insert a part from an external file without opening it as a document. On the flip side, the process of setting all LCSs is rather tedious, and attaching one part to another means you have to make more clicks than what you typically get with regular constraints.įinally, Assembly 4 supports both top-down and bottom-up design models. We’ve seen multiple testimonials that the approach to assembling a model through LCS proves to be more predictable and robust. It is, however, possible to “release” a DOF by using the attachment offset property and expressions. Once both LCSs are aligned, all six degrees of freedom are fixed, and thus parts stay attached no matter what. ![]() Then when a new part is inserted into an assembly, the user specifies the parent part (which part to attach to), the source LCS (from the newly inserted part), and the target LCS (from the parent part): The kind of a feature an LCS is attached to defines what attachment options are available. Which makes it unaffected by the dreaded toponaming issue (now being finally taken care of in upstream FreeCAD). However, if the geometry of that part changes, the LCS stays where it was. When an LCS is originally created, it is attached to a very specific feature of a part. For example, the part on the screenshot below has 5 of them: Each body in a part can have multiple local coordinate systems. vertex to vertex), the workbench maps one local coordinate system (LCS) to another. Secondly, rather than aligning characteristics of two parts (e.g. ![]() The workbench also has the concept of a variant link which allows referencing the same object multiple times and using different parameters for each of the linked instances. This makes models cleaner, and you always work with up-to-date geometry. In a nutshell, rather than creating a full copy of a part, FreeCAD will reference it. Workflow and ease of use Īssembly 4 relies on several core principles.įirst off, it is built around the App:Link API that we already mentioned in previous posts in the series. So far, A4 is the only assembly workbench where the development pace is about the same as it was when the project started, and Zolko isn’t done yet. Just like with other assembly workbenches, much of the development has been affected by the user community, and a number of features have been contributed by other developers. Zolko came to the community with extensive knowledge of other CAD programs such as Pro/E, Catia, and T-Flex, but he was very (and probably needlessly) humble about his programming skills. The project was started by Zolko in 2019 after some experiments with building assemblies without solvers. In the previous posts in this series, we talked about the need for a default assembly workbench in FreeCAD and reviewed Assembly 2, A2plus, and Assembly 3.
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