The Feature Tree and parts¶

The Feature Tree is the model. The viewport shows what it currently evaluates to; the tree is the thing you actually edit.

This page is the reference for the Feature Tree panel and for the Active CAD Workspace panel above it. For why it works this way, see How it works.

A row¶

Each row is one operation, and carries these controls, left to right:

Control	What it does
Radio button	Makes the entry active. The Active Property Editor below then shows its parameters
Checkbox	Marks the entry for Group Selection (see below). Nothing else uses it
Name and icon	Also makes the entry active. The icon reflects the operation type
Duplicate	Copies the entry and makes the copy active
X	Deletes the entry
Eye	Suppresses the entry: it stays in the tree but is left out of the model (see below)
Pin	Sets or clears the rollback point

Rows below an active rollback point are greyed out and their buttons are disabled. A suppressed row is dimmed but stays clickable.

To rename an entry, make it active and edit the name at the top of the Active Property Editor. The proxy object in the outliner is renamed with it. If the name is already taken, Blender adds .001 and the tree follows.

Entries inside a group are indented, so nesting is visible at a glance.

Curve entries expand in place¶

When a Curv, Plin or Surf entry is the active one, the tree expands underneath it and lists every control point as an editable P0, P1, … with add and remove buttons per point, plus Add Point at the end. Polyline points additionally get a per-corner fillet toggle.

This is the only place those points can be edited numerically.

Order is creation order, and it is fixed¶

The tree is evaluated top to bottom, and position is creation order.

Two things follow, and they are worth knowing before you build something long:

Rows cannot be reordered. There is no move-up or move-down.
New operations are always appended to the end. There is no way to insert one into the middle. Setting a rollback point does not change this — a new entry created while a pin is set still lands at the bottom, below the pin, where it is greyed out and not evaluated. If a shape you just created did not appear, check whether a pin is set.

So think about order as you build. If you need an operation earlier than everything you have already made, the practical options are to delete and redo the later entries, or to change what the existing entries do:

Change an entry's Operation — the same shape cutting instead of fusing often gets you where reordering would have
Use a group so a run of entries combines as one unit
Split into two parts with Base and Separate Previous to New Part
Suppress an entry to see or build the model without it, instead of deleting it

The one exception is Edit Sketch: re-editing a sketch rebuilds its entry in place and keeps its original position, so downstream fillets stay attached. That holds as long as the sketch still produces the same number of separate closed regions. If that number changes, the rebuilt entry goes to the end and the add-on warns you that downstream features may need reassigning.

Operation¶

Every entry combines with the accumulated result of everything above it, according to its Operation, set in the Property Editor:

Value	Effect
`Base`	Discard everything above and start fresh from here
`Add (Fuse)`	Union. The default
`Subtract (Cut)`	Cut out of the result so far
`Intersect (Common)`	Keep only the overlap

Base, and splitting a part¶

An entry set to Base cuts the history in two: everything above it stops contributing. The Property Editor then offers Separate Previous to New Part, which turns that discarded upper portion into a part of its own instead of leaving it inert.

It asks which of two things you want:

Mode	Effect	Risk
Move (Clean up original)	Moves the earlier entries out of this part	Anything below that referred to them — a fillet's target face, a pattern's target — loses its reference
Copy (Keep references)	Copies them to the new part and leaves them here as history	Safe for references; the original stack keeps growing

Choose Copy unless you have checked that nothing below depends on the entries being moved.

Rollback¶

The pin sets a rollback point. Evaluation stops there; everything below is ignored and greyed out. Pressing the pin on the row that already holds it clears it.

Rollback has three distinct uses:

Inspecting an intermediate state
Editing safely — hiding downstream operations while you change something they depend on
Performance. Everything below the pin stops being evaluated, which is the most effective single thing you can do to keep a long history responsive while you work on an early operation

Some controls are deliberately disabled while a rollback point hides their target — Edit Sketch is the one you will meet. The panel says "Hidden by rollback point" rather than doing nothing silently.

Suppress¶

The eye icon takes one entry out of the model without deleting it. Press it again to bring the entry back.

It differs from rollback in one way that matters: rollback stops everything below the pin, while suppress removes only that row. Everything below it keeps evaluating.

A suppressed Mirror, Array or other entry that acts on a target no longer uses that target, so the original shape shows again.

Fillets and other edge or face picks below a suppressed row can change. They refer to specific edges and faces, and removing a shape above them changes which edges exist. In testing, suppressing one of two fused boxes left a fillet on only some of its edges, and suppressing the box the fillet was picked on removed the fillet entirely, with no error. Un-suppressing restores both.

Parameters¶

The Parameters panel (closed by default) holds named values for the active part, and lets any entry take a field from an expression.

Add Parameter creates a row with a name and an expression, and shows the value it evaluates to. Expressions may use:

numbers and other parameter names: width / 4 + 1
+ - * / // % ** and parentheses
sqrt sin cos tan radians degrees abs min max round floor ceil, and pi

Nothing else is accepted, on purpose — a .blend file may come from someone else, so an expression can never run code.

Below the list, Drive a Field binds a field of the active entry to an expression: Size X/Y/Z, Location X/Y/Z, Rotation X/Y/Z (in degrees), Radius, Radius 2, Minor Radius, Pipe Radius, Extrude Height, Value/Angle, Count, Sides/Teeth, Turns, Module, Angle Start and Angle End. The expression starts as the field's current value, so binding a field does not change the shape.

Things to know:

A driven field follows its expression. If you move it by hand — typing a number, or dragging the proxy — it goes back to the expression's value the next time any parameter changes. The panel says so when an entry has driven fields.
Renaming a parameter updates the expressions that use it. width becomes w everywhere; width2 is left alone.
Errors do not break the model. A circular reference, an unknown name or a typo is shown in red on that row, and the field keeps its last good value.
Driven fields are kept when an entry is duplicated or grouped.

Groups¶

Group ( and Group ) insert a matching pair of markers. Everything between them is treated as one unit when it combines with the rest of the model, rather than each entry combining one at a time.

Group Selection, at the top of the panel, wraps the rows you have checked in a new group. It has rules, and it tells you when you break one:

At least two rows, and they must be a contiguous range. Checking rows with a gap between them is refused
Existing group boundaries cannot be crossed. A new group must nest cleanly inside or outside an old one, not straddle its edge
If a row inside the new group references a primitive outside it — a sweep path, a loft profile, a pattern target — you are warned, because the reference now crosses a group boundary

Targets: entries that point at other entries¶

Not every entry contains its own geometry. Mirror, Array, Circ, Link, Sweep and Loft act on another entry, referred to by an internal UUID rather than by position. Two controls set that reference:

Pick Target (list) — a dialog listing the other entries in this part by name
Pick Target in Viewport — click the object in the viewport instead

Because the reference is a UUID, it survives edits above it in the tree. It does not survive the target being deleted, or being moved to another part by Separate Previous to New Part in Move mode.

Modifier entries — Fillet, Chamfer, Offset, Inset, Draft, Shell — work differently. They refer to specific faces or edges picked in Selection Mode, not to whole entries.

Parts¶

The Active CAD Workspace panel, at the top of the sidebar, selects which part you are editing.

Control	What it does
Dropdown	Chooses the active part
Add New CAD Part	Creates another, independent part
Trash icon	Deletes the active part and frees its geometry

Every panel below it applies to the active part only. If those panels are missing entirely, no valid part is selected — pick one from the dropdown.

In Blender's outliner, parts are collections: Part_1, Part_2, … inside a Seamless_CAD collection, plus a Result collection that receives baked meshes. Numbering fills the first free name, so deleting Part_2 and adding a new part gives you Part_2 again, not Part_3.

Only the active part is evaluated. Splitting a model into several parts is therefore a performance tool as well as an organisational one — see Quality and performance.