Working with Several Bodies

A Kapy document holds as many solid bodies as you like. How you split a model into bodies, and when you merge them, decides how easy the file is to edit for the rest of its life.

Keep them separate, join them late

Two habits keep a multi-body document editable.

Model distinct things as distinct bodies. A hinge and its pin, a case and its lid, a bracket and the boss it carries: each keeps its own history and can be edited, hidden, exported or thrown away without disturbing the others.

Join at the end, not as you go. An extrude set to Add joins as it builds, which is fewer clicks and a worse document. From that moment the two shapes are one, and changing either means editing a feature buried further up the tree. Build them separately and finish with a Union. That costs one step and leaves both halves editable.

The exception is the obvious one. When the second shape only exists as part of the first, a rib on a wall or a boss on a plate, use Add, because there was never a second thing.

The active body

One body is active at a time, and a new feature attaches itself to the active body when nothing else says otherwise. The active body decides where your next extrude lands.

Double-click a body in the viewport to make it active. That is the whole interface: double-clicking makes a body active as well as selecting it, there is no dropdown to set it, and a single click only selects.

The active body survives a rebuild as long as it does. It is only re-chosen when the body it pointed at is gone, consumed by a boolean or orphaned by a deleted feature, and then it falls to the newest survivor.

If a new feature attaches itself to a body you did not expect, check which one is active. Double-click the body you meant, then build the feature again.

Names, colours, visibility

The Bodies window is where a body becomes recognisable rather than "Body 4".

• Rename one and the name sticks. If the body came from a boolean, renaming it renames the timeline step too, because for those the body and the feature are the same idea.
• Colour comes from a palette of sixteen, handed out in order, so a document with several bodies is legible from the first one. Override it from the swatch, and the choice survives every rebuild.
• Hide a body and it stops being drawn and stops being exported. It still takes part in the model itself: it is still cut, still fused, still in the way of a boolean. Hide a body to declutter the view, not to park a body you still want in the file you download. The one exception is a print support: it is real printed material, so it goes into an STL whether it is hidden or not.

Open the Bodies window and show every body you want before you export. A hidden body is simply missing from the STL or STEP you get back, and nothing warns you.

Deleting

There is no delete on a body. A body exists because a feature made it, so get rid of it by deleting the feature in the timeline that produced it.

See also

• Union and Intersect: joining bodies at the end
• Subtract: and removing one from another
• Saving Your Work: what leaves the document when you export