Autodesk Fusion 360 Quiz: Combine Operations
10 questions · exam conditions
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Combine OperationsQuestion 1 of 10

A small solid plug lies completely inside a larger solid block. The block is selected as the Target Body, the plug is selected as the Tool Body, Operation is set to Intersect, and Keep Tools is disabled.

Which result should the designer expect?

The target becomes the plug-shaped common volume, and the original tool body is consumed.
The target becomes the block minus the plug, and the original tool body is consumed.
The target remains the complete block, while the internal plug becomes a separate body.
The target becomes the plug-shaped common volume, while both original bodies remain unchanged.
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Autodesk Fusion 360 Quiz

Autodesk Fusion 360 Quiz: Combine Operations

Practice Combine Operations in Autodesk Fusion 360 with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

What this quiz covers

This quiz focuses on Combine Operations, giving you a quick way to practice the rules, question types, and explanations that matter most for Autodesk Fusion 360.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

All questions

Question 1

A small solid plug lies completely inside a larger solid block. The block is selected as the Target Body, the plug is selected as the Tool Body, Operation is set to Intersect, and Keep Tools is disabled.

Which result should the designer expect?

  1. The target becomes the plug-shaped common volume, and the original tool body is consumed. (correct answer)
  2. The target becomes the block minus the plug, and the original tool body is consumed.
  3. The target remains the complete block, while the internal plug becomes a separate body.
  4. The target becomes the plug-shaped common volume, while both original bodies remain unchanged.
Explanation: When working with Fusion 360's Combine tool, you need to track three things simultaneously: what happens to the Target Body, what happens to the Tool Body, and what the Keep Tools toggle controls. The Intersect operation retains only the volume shared by both bodies — the geometric intersection. Since the plug lies entirely inside the block, their shared volume is exactly the plug's shape. The Target Body is replaced by this common volume, so the large block is discarded and what remains in its place is a plug-shaped solid. This confirms A as correct. The Keep Tools setting determines whether the Tool Body survives after the operation. With Keep Tools disabled, the tool body is consumed — it disappears after contributing its geometry to the calculation. So the plug-shaped result is the only body remaining, and both original forms are gone. B describes a Cut (or Subtract) operation, not Intersect — subtracting the plug from the block leaves a block-with-hole, which is the wrong operation entirely. C describes no operation at all; bodies don't reorganize themselves simply by being selected. It also misrepresents how Combine works — the Target is always modified or replaced, never left untouched. D is tempting if you confuse "Keep Tools enabled" with the default state — keeping both bodies unchanged is what happens when Keep Tools is on, not off, and even then the target would still be transformed. A reliable memory hook: Intersect = only the overlap survives in the target. Keep Tools ON = tool lives; Keep Tools OFF = tool is consumed.

Question 2

Body P has a volume of 100 cm3100\text{ cm}^3. Body C has a volume of 40 cm340\text{ cm}^3, of which 30 cm330\text{ cm}^3 overlaps Body P. A designer intends to cut C from P but accidentally selects C as the Target Body and P as the Tool Body. Keep Tools is disabled.

What is the resulting volume of the surviving target body?

  1. 10 cm310\text{ cm}^3, because the portion of C inside P is removed from C. (correct answer)
  2. 30 cm330\text{ cm}^3, because only the overlapping region is retained as the result.
  3. 70 cm370\text{ cm}^3, because C is subtracted from P despite the reversed selections.
  4. 110 cm3110\text{ cm}^3, because the nonoverlapping portions of both bodies are combined.
Explanation: When working with Combine operations in Fusion 360, always ask yourself: which body is the Target, and which is the Tool? The Target Body is the one that survives the operation (assuming Keep Tools is off), and the Tool Body defines the shape being used to modify it. The Cut operation removes the Tool's volume from the Target — it does not matter what the designer intended. Here, the designer accidentally assigned Body C (40 cm340\text{ cm}^3) as the Target and Body P (100 cm3100\text{ cm}^3) as the Tool. Fusion 360 executes exactly what it's told: it cuts P away from C. The overlapping region — 30 cm330\text{ cm}^3 of C that intersects P — gets removed from C. The remaining volume of C is 40−30=10 cm340 - 30 = 10\text{ cm}^3. Since Keep Tools is disabled, Body P is deleted entirely. Answer A is correct. Answer B (30 cm330\text{ cm}^3) describes an Intersect operation, which retains only the shared volume — that's a completely different Combine type. Answer C (70 cm370\text{ cm}^3) reflects what would have happened with the correct selection — P minus the overlap — but the selections were reversed, so this doesn't apply. Answer D (110 cm3110\text{ cm}^3) describes a Join operation that adds non-overlapping volumes together, which is neither Cut nor what occurred here. A reliable study tip: before confirming any Combine operation in Fusion 360, visually verify the Target and Tool assignments in the dialog. The Target survives; the Tool shapes or destroys. Swapping them produces an entirely different — and often irreversible — result.

Question 3

In a design with history enabled, an obsolete construction body must disappear from all later operations. The designer wants a timeline feature that can be suppressed or edited later, rather than erasing the body's originating history.

Which body-management action is most appropriate?

  1. Hide the body in the Browser so later features no longer reference its geometry.
  2. Use Remove so the body's removal is recorded as a feature in the timeline. (correct answer)
  3. Use Delete so the body and its originating creation feature are permanently discarded from the design.
  4. Use Combine Cut with the obsolete body as both target and tool to eliminate it parametrically.
Explanation: When working with body management in Fusion 360's parametric (history-enabled) environment, the key distinction to understand is timeline participation. Some actions record a feature in the timeline that you can later suppress, edit, or reorder — others permanently alter the design history in ways you can't easily undo parametrically. Remove is the correct tool here precisely because it creates a dedicated timeline entry. This means the body's elimination is reversible: you can suppress the Remove feature to restore the body, right-click to edit it, or reorder it relative to other features. The body's originating creation feature stays intact in the timeline — nothing upstream is destroyed. This matches exactly what the passage describes. Choice A is tempting but wrong: hiding a body in the Browser is purely a visibility toggle. The body still exists geometrically, meaning downstream features can still accidentally reference it. This doesn't reliably remove it from the design's computational pipeline. Choice C describes Delete, which is the critical trap here. Delete removes the body and its originating creation feature from the timeline — it's a destructive, non-parametric erasure. You lose the history entirely, which is the opposite of what the question requires. Choice D is a creative but incorrect workaround. Using Combine Cut with the same body as both target and tool doesn't produce a clean, reliable result in Fusion 360, and it obscures intent — the timeline entry would be confusing and unpredictable. A useful rule of thumb: on questions involving "reversible" or "editable" body changes in Fusion 360, always look for the action that writes a timeline feature — that points you to Remove over Delete or browser toggles.

Question 4

Two solid bosses are separated by a gap, but the finished part must be one contiguous printable solid. A rib is to fill the gap and connect the bosses.

Which modeling sequence is the most reliable?

  1. Run Join on the separated bosses first, then create a rib that stops short of both bosses.
  2. Enable Keep Tools during Cut so the empty gap is converted into connecting solid material.
  3. Run Intersect on the separated bosses, then use the retained common volume as the rib.
  4. Create a rib body that overlaps both bosses, then use Join to unite the connected solids. (correct answer)
Explanation: When connecting separate solid bodies in Fusion 360, your goal is to create geometry that physically bridges the gap and then merge everything into one watertight solid. The key principle: overlap first, then join — this guarantees no accidental gaps at the interfaces. Creating a rib body that intentionally overlaps into both bosses (answer D) is the reliable approach because the overlap ensures the rib's faces penetrate the boss surfaces, eliminating any risk of a near-miss tangency that leaves invisible gaps. Once the rib overlaps both bosses, the Join command merges all three bodies into a single contiguous solid — exactly what the finished part requires. Answer A fails because running Join on the two separated bosses before creating the rib doesn't help — the bosses don't touch, so Fusion 360 cannot join non-overlapping bodies. The gap still exists, and a rib that "stops short" would leave the assembly disconnected. Answer B confuses the Cut operation with a material-adding workflow. Cut removes material; it cannot fill a gap or generate new solid geometry. "Keep Tools" simply preserves the cutting body afterward — it doesn't create connecting material in the empty space. Answer C misunderstands the Intersect operation. Intersect retains only the overlapping volume shared between selected bodies. Since the bosses are separated and share no common volume, Intersect would eliminate both bodies entirely, leaving nothing. Study tip: In Fusion 360 Boolean problems, remember the sequence — build geometry that overlaps, then combine. If geometry doesn't physically touch before a Boolean operation, Join and Intersect will either fail or produce unexpected results.

Question 5

An imported design contains three separate solid bodies under one component. Each solid must appear separately in the bill of materials and must accept its own assembly joint. Their geometry must not be fused.

Which action best prepares the design for assembly work?

  1. Use Combine Join on all three bodies, then assign three joints to the resulting solid.
  2. Use Combine Intersect with Keep Tools so each body's assembly identity is preserved.
  3. Use Create Components from Bodies so each solid receives its own component context. (correct answer)
  4. Use Remove on two bodies and keep the remaining body as the complete assembly component.
Explanation: When working with multi-body designs in Fusion 360, the key distinction to understand is the difference between bodies and components. Bodies are raw geometry; components are the organizational units that carry assembly identity — they appear as independent line items in the BOM and can host joints, appearances, and physical materials independently. Create Components from Bodies (option C) is precisely the tool for this situation. It converts each selected body into its own component while preserving the original geometry untouched. After running this command, each solid lives inside its own component context, shows up as a separate BOM entry, and can receive its own assembly joints — exactly what the scenario requires. Option A fails because Combine Join merges all three bodies into a single solid. You'd end up with one unified piece of geometry, making it impossible to assign independent joints or BOM entries to the original three shapes. This is the opposite of what you need. Option B is a trap for students who confuse Combine tools with organizational tools. Combine Intersect creates geometry from the overlapping volume of bodies — it doesn't preserve individual assembly identity. "Keep Tools" retains the original bodies geometrically but still doesn't give them component contexts. Option D defeats the purpose entirely. Removing two bodies discards geometry permanently, leaving you with only one solid rather than three separate assembly-ready components. A useful rule of thumb: whenever a question mentions BOM entries, joints, or independent assembly behavior, think components first. If your solids don't yet live in their own components, Create Components from Bodies is your starting point.

Question 6

A cutter body is used in a Combine Cut with Keep Tools enabled. Later in the timeline, a Move/Copy feature relocates the retained cutter. The designer expects the earlier cut to move automatically, but the pocket remains in its original location.

What change best makes the Combine feature use the cutter's relocated position?

  1. Run Compute All, because the timeline evaluates features from newest to oldest and will pick up the moved position.
  2. Disable Keep Tools so that the later Move/Copy feature propagates its changes backward to the Combine feature.
  3. Change the Combine operation from Cut to Join, relocate the cutter, then switch the operation back to Cut.
  4. Reorder or recreate the Move/Copy feature before the Combine feature so the cut evaluates using the cutter's new position. (correct answer)
Explanation: Whenever you see a question about Fusion 360's parametric timeline, think about evaluation order: the timeline replays features sequentially from top to bottom, so each feature only "knows about" the state of the model at the moment it was originally placed. In this scenario, the Combine Cut happens before the Move/Copy in the timeline. When Fusion 360 replays, it executes the cut first using the cutter's original position, then moves the cutter afterward. The pocket is already carved before the relocation ever occurs — the cut has no awareness of the later move. The fix is to place the Move/Copy before the Combine feature so that when the cut evaluates, it reads the cutter's already-relocated position. That's exactly what D describes: reordering or recreating the Move/Copy earlier in the timeline so the geometry is in its new location when the Combine feature runs. A is wrong because Compute All simply replays the entire timeline in the same top-to-bottom order — it doesn't reverse that order or allow downstream features to influence upstream ones. B is incorrect because disabling Keep Tools only determines whether the cutter body survives after the operation; it has nothing to do with propagating positional changes backward through the timeline. C is a red herring — temporarily switching to Join and back does not alter the timeline's evaluation order, so the cut pocket still forms at the original position. As a study tip, remember: in Fusion 360, earlier features never "see" changes made by later features. When a result surprises you, ask yourself, "Is the feature that needs updated information after the feature providing that information in the timeline?"

Question 7

A solid housing must be divided by a planar construction surface so that the two resulting portions remain as separate editable bodies. No material should be removed between the portions.

Which workflow most directly produces the required result?

  1. Use Combine Cut with the housing as target and the construction surface as the tool.
  2. Use Split Body with the housing as the body and the construction surface as the splitting tool. (correct answer)
  3. Use Combine Intersect and enable Keep Tools to retain both sides of the housing.
  4. Use Combine Join after copying the housing to preserve both resulting portions.
Explanation: When working with solid bodies in Fusion 360, it helps to distinguish between operations that divide geometry and those that combine or intersect multiple bodies. The key requirement here is splitting one body into two independent, editable bodies without removing any material — that's your guiding filter. Split Body is purpose-built for exactly this scenario. You select the target body (the housing) and a splitting tool (your planar construction surface), and Fusion 360 divides the solid into two separate bodies that both remain in the Bodies folder, fully editable. No material is consumed or discarded — the split surface simply acts as a dividing plane. This makes B the correct workflow. Choice A misapplies the Combine tool's Cut operation, which uses one body's volume to remove material from another — it doesn't divide a single body cleanly into two retained halves. Choice C, Combine Intersect, keeps only the overlapping volume between two bodies; even with Keep Tools enabled, it's designed for multi-body intersections, not for dividing a single solid into complementary halves. Choice D, Combine Join, merges bodies together rather than separating them — copying the housing first doesn't change the fact that Join produces a unified result, not two distinct portions. A useful study tip: whenever a question describes dividing a single body into parts with no material loss, Split Body is almost always the answer. Reserve Combine operations (Cut, Join, Intersect) for scenarios involving two or more existing bodies interacting with each other. Keeping that distinction clear will help you quickly eliminate distractors on similar questions.

Question 8

A designer creates a body representing the required clearance envelope around a purchased motor. The envelope must first cut a pocket into a housing and then be reused to check interference with a separate cover.

Which Combine workflow best supports both tasks without recreating the clearance envelope?

  1. Cut the housing with the envelope and enable Keep Tools so the envelope remains available. (correct answer)
  2. Cut the envelope with the housing and disable Keep Tools so the housing remains available.
  3. Intersect the housing with the envelope and enable Keep Tools so both exterior volumes remain.
  4. Join the housing with the envelope and disable Keep Tools so the clearance volume becomes internal.
Explanation: When working with the Combine tool in Fusion 360, always ask yourself two questions: What operation do I need? and Do I need to preserve the tool body afterward? The "Keep Tools" toggle is the critical control that lets you reuse a body across multiple operations without rebuilding it. In this scenario, the clearance envelope acts as a tool body — it defines the shape you want to remove from the housing. Choosing Cut removes the envelope's volume from the housing (the target body), creating the pocket you need. Enabling Keep Tools ensures the envelope body survives the operation intact, leaving it available for the subsequent interference check against the cover. That's exactly what A describes, making it the correct workflow. B reverses the roles — cutting the envelope with the housing makes no geometric sense here and discarding the housing defeats the entire purpose. C uses Intersect, which retains only the overlapping volume between the two bodies. This would destroy the housing's non-overlapping geometry, not create a pocket within it. Enabling Keep Tools here wouldn't save the exterior volumes — it only preserves the tool body, not the original shape of the target. D uses Join, which merges volumes together rather than subtracting one from the other. Disabling Keep Tools then consumes the envelope, so you lose the very body you need to recheck interference. A useful rule of thumb: whenever a tool body needs to serve multiple purposes across a workflow, your first instinct should be to enable Keep Tools. Think of it as borrowing a shape rather than consuming it.

Question 9

A plate is one solid body. Two cylindrical solid bodies pass through the plate and do not overlap each other. In Combine, the plate is selected as the Target Body, both cylinders are selected as Tool Bodies, Operation is set to Cut, and Keep Tools is enabled.

After the Combine feature computes successfully, what remains in the design?

  1. One plate body containing two holes; both cylindrical tool bodies are consumed.
  2. One plate body containing two holes and two separate cylindrical tool bodies. (correct answer)
  3. One plate body containing two holes and one merged cylindrical tool body.
  4. Two plate bodies around the holes and two separate cylindrical tool bodies.
Explanation: When working with Fusion 360's Combine feature, you need to track two independent settings: what happens to the Target Body and what happens to the Tool Bodies. The Cut operation subtracts the Tool Bodies' shapes from the Target Body — but "Keep Tools" is a separate toggle that controls whether the Tool Bodies survive after the operation. With "Keep Tools" enabled, Fusion 360 performs the cut geometry on the Target Body while preserving the Tool Bodies as independent solid bodies in the design. That's exactly what happens here: the plate (Target) gets two cylindrical holes cut through it, and both cylinders remain in the browser as separate, intact bodies. This makes B the correct answer. A describes what happens when "Keep Tools" is disabled — the cylinders would be consumed during the cut and disappear from the design. Since Keep Tools is explicitly enabled in this scenario, this is the trap answer many students fall into. C incorrectly suggests the two cylinders merge into one body. The Combine-Cut operation never merges Tool Bodies together; they remain distinct. Merging would require a Join operation between the cylinders themselves. D implies the plate splits into two separate bodies, which would only occur if the cylinders had completely divided the plate into disconnected regions. Since the cylinders are described as not overlapping and passing through the plate (not severing it entirely), the plate remains one continuous body. Study tip: Memorize this toggle: Keep Tools = OFF means tool bodies vanish after the operation; Keep Tools = ON means they survive. Exam questions frequently test this single distinction.

Question 10

A tool body touches a target body only along a single edge. The bodies have no overlapping volume and no shared face area. The designer selects Combine with Operation set to Join.

Why is this operation unlikely to create the intended single solid?

  1. Join requires the tool to be completely enclosed by the target before their volumes can merge.
  2. Join always preserves both input bodies, so touching bodies cannot become one solid body.
  3. Edge-only contact can produce invalid non-manifold geometry rather than a valid solid union. (correct answer)
  4. The target must have less volume than the tool whenever Join is used on contacting bodies.
Explanation: When working with Fusion 360's Combine tool, you need to think about what "joining" bodies actually requires geometrically: two bodies must share overlapping volume or at least a shared face area so the modeler can merge them into a single, watertight solid. The nature of contact between bodies determines whether a valid result is even possible. When two bodies touch only along a single edge, no volume overlap exists — they meet at a one-dimensional boundary. Attempting to join them produces what's called non-manifold geometry, where an edge is shared by more than two faces or connects bodies in a way that cannot represent a physically valid solid. Fusion 360's solid modeling kernel requires manifold geometry, so this operation either fails or produces an invalid, unusable body — not the clean single solid you intended. That's why C is correct. A is wrong because Join does not require the tool to be enclosed by the target. Join simply merges overlapping volumes — full enclosure is a concept associated with operations like Intersect, not Join. B is incorrect because Join does not preserve both bodies; it consumes the tool body and merges it into the target. That's actually the whole point of the Join operation. D is fabricated — there is no volume-size requirement between tool and target bodies when using Join. As a study tip, remember the phrase "face contact, not edge contact" when using Join. Solid Boolean operations in Fusion 360 need shared face area or overlapping volume to produce valid results — edge-only or point-only contact will almost always cause non-manifold errors.