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Compatibility: which geometry an object answers to

A red row in the project tree means an object measures DOFs that the geometry it answers to does not have. Nothing is blocked by it — the object plots, exports and computes as before — but a shape cannot be drawn on a node that is not there, and a report figure that needs the geometry will say so. This page is the rule, the marks, and the one act the rule refuses.

The rule

An object linked into a group that holds a geometry is judged against that geometry — a link is a declaration that these things belong together, and the group's geometry is the one its shapes and channels are meant for. Everything else is judged against the active geometry: the one marked in the tree, or the first one in the project until one is chosen. Right-click a geometry and choose Set as Active Geometry to change it; the active one is drawn bold with a bullet beside its icon, because bold alone did not stand out among the darker real objects.

Every DOF of a data object, shape set or channel table has to be a node in that geometry, in a direction the node can carry. A geometry that has the nodes is compatible whatever its units, and a project with no geometry at all has nothing to judge against and marks nothing.

The marks

  • A red row in the tree, with the reason on hover: how many DOFs are missing out of how many, which ones (the first six, then and N more), and which geometry was asked — for example 3 of 678 shape DOFs are not in geometry 'plate': 501X+, 501Y+, 501Z+.
  • A red sub-row where the object expands: the record, mode or channel that carries the missing DOF is marked, not only its parent.
  • The same reason in a script: project.compatibility() returns a report whose issue_for(name) gives the issue for one object, with its missing_dofs, and incompatible_names lists every marked object.

What is refused

Linking. project.link — and the link bar in the window — refuses to put an object into a group whose geometry lacks its DOFs, and says which DOFs. A group is a promise that its members fit together, and a link that broke the promise on the way in would have to be marked red the moment it was made.

The obvious alternative — an object is compatible if any geometry in the project can display it — was considered and rejected. It reads naturally with two demonstration models loaded side by side, and it is wrong the moment a project holds a test geometry and a model geometry that share node numbers: a shape set would be judged against whichever happened to fit, and the answer would change when a geometry was added or removed. The group's geometry, and otherwise the active one, is an answer the user chose.