Mass budget from a Fusion design

The problem this solves

A mass budget built from CAD looks authoritative whatever it is made of. Somewhere in the total is a component with no material assigned and a number somebody typed in as a placeholder, and once it is summed with the computed masses nobody can tell them apart. The margin then rests on a figure nobody would defend if asked.

How it works

What the hardware actually weighs, rolled into the budget, with placeholder masses kept apart from real ones. A mass computed from geometry and an assigned material is evidence. One typed in as a placeholder is not, and the two are never added into the same total without saying so.

What you need

Autodesk's own Fusion MCP, connected through the Fusion desktop app with your Autodesk account. The separate Fusion Data MCP covers projects, folders and permissions rather than geometry, so it is not needed for these.

You are reading component mass and physical properties from an
Autodesk Fusion design and using them to update the mass budget in
the Dalus model [model name]. The model holds the budget, its
allocations and its margin; Fusion holds what the hardware actually
weighs. This workflow closes that gap and reports what moved.

CHECK THE CONNECTION FIRST: confirm Fusion is running, report the
active document and its version or last-saved date, and confirm the
Dalus model is reachable. If no document is open, ask which to open
rather than guessing.

CONFIRM FIRST, in one message: which Dalus model and branch; which
Fusion design and which configuration or variant of it; the scope
(whole assembly or named subassemblies); which properties to pull
(mass, volume, centre of mass, material, bounding dimensions); how
components map to model parts, meaning a part number attribute, a
naming convention, or nothing yet; and whether a previous run exists
to compare against. Ask anything else in the same message. Then
begin.

TREAT FUSION AS READ-ONLY. Read properties; never modify geometry,
parameters, materials or the assembly, and never save the document.
The design is a controlled artefact exactly as the model is.

READ THE FUSION SIDE: the component tree in scope, and per component
its name, part number or identifier where set, occurrence count,
mass, material, and whether the mass is computed from geometry and
material or overridden manually. Record the source per value.

DISTINGUISH COMPUTED FROM OVERRIDDEN, and carry it through
everything. A mass computed from real geometry and an assigned
material is different evidence from one typed in as a placeholder,
and the budget's credibility rests on the difference. Where Fusion
records no material or a default one, the mass is not evidence and
must be reported as such rather than absorbed into a total.

MATCH COMPONENTS TO MODEL PARTS, and show the matching. State per
item how it was made: part number, exact name, documented alias, or
inferred from position in the tree. Mark inferred matches. Items you
cannot match go in their own lists and are never forced into pairs:
- In Fusion, not in the model: hardware nobody has in the
  architecture. Often fasteners and brackets, which may be
  deliberate, so group the small ones and lead with the substantial
  ones by mass.
- In the model, not in Fusion: parts with no physical
  representation. Either not yet designed, or bought-in items that
  live outside CAD, and the distinction matters.

MULTIPLICITY: apply occurrence counts from the assembly, and compare
them against the multiplicities the model records. A component
appearing six times in CAD against a model that says four is a
finding in its own right and is reported before any total.

ROLL UP through the model hierarchy, showing contributions per level
with the arithmetic visible. Children must sum to parents and
parents to the system. If they do not, stop and report it rather
than publishing a total that does not add up.

REPORT THE MARGIN honestly: current best estimate from CAD, the
allocation or limit with its requirement ID, the margin in absolute
terms and as a percentage, and the coverage, meaning what share of
the total comes from computed masses, what share from overrides, and
what share of the model has no CAD mass at all. A total with 60%
coverage is a different object from one with 95% and the report must
never let them look alike.

THE DELTA, if a previous run exists: total change, which components
grew and by how much, largest first, components added or removed
since last time, and the resulting margin movement. Where growth is
steady, say what the rate implies: at this rate the margin reaches
zero in roughly this many weeks. That sentence is the one people
act on.

FINDINGS: subsystems over their allocation, components with no
material assigned, overridden masses that have not been replaced by
computed ones across several runs, occurrence-count disagreements,
and the largest contributors, since attention goes there first.

OFFER, DO NOT EXECUTE: writing the CAD masses onto the model's parts
as attributes, gated per part and preserving the computed-versus-
overridden distinction; opening tasks for components with no
material; and re-running before the next review so the delta
accumulates.

THIS WORKFLOW IS READ-ONLY on the Fusion design and on the Dalus
model unless the user approves the write-back per part.

Replace the [bracketed] placeholders with your model and project names.

What you get

Common questions