Autodesk Fusion 360 Quiz: As Built Joints
10 questions · exam conditions
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As Built JointsQuestion 1 of 10

Two imported components have already been positioned correctly: a sensor bracket is seated against a machine frame, and its mounting holes are aligned. The designer now needs the bracket to remain fixed to the frame without changing its current location.

Which workflow most directly preserves the existing placement while defining the required assembly relationship?

Create a regular rigid Joint and allow its selected joint origins to reposition the bracket.
Create a rigid As-Built Joint between the bracket and frame at their current positions.
Use Align on the mounting faces and leave the components without an assembly joint.
Ground the bracket and create a revolute As-Built Joint to the machine frame.
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Autodesk Fusion 360 Quiz

Autodesk Fusion 360 Quiz: As Built Joints

Practice As Built Joints 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 As Built Joints, 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

Two imported components have already been positioned correctly: a sensor bracket is seated against a machine frame, and its mounting holes are aligned. The designer now needs the bracket to remain fixed to the frame without changing its current location.

Which workflow most directly preserves the existing placement while defining the required assembly relationship?

  1. Create a regular rigid Joint and allow its selected joint origins to reposition the bracket.
  2. Create a rigid As-Built Joint between the bracket and frame at their current positions. (correct answer)
  3. Use Align on the mounting faces and leave the components without an assembly joint.
  4. Ground the bracket and create a revolute As-Built Joint to the machine frame.
Explanation: When working with assembly constraints in Fusion 360, you need to distinguish between tools that set a position versus tools that lock in an existing one. This question tests your understanding of As-Built Joints versus regular Joints and when each is appropriate. The key here is that the components are already correctly positioned. An As-Built Joint captures components exactly where they currently sit in the workspace — no repositioning occurs. A rigid As-Built Joint specifically locks all six degrees of freedom while honoring the current placement, which is precisely what the scenario requires. That makes B the correct choice: it defines the assembly relationship without disturbing the bracket's location. A is a trap because a regular rigid Joint uses selected joint origins to calculate and move components into alignment. Even if you pick the right geometry, Fusion 360 will reposition the bracket to satisfy the joint definition — exactly what you're trying to avoid. C might seem reasonable since Align can reposition faces without changing the intent, but leaving components with no assembly joint means there's no parametric relationship defined. The bracket isn't truly constrained; it's just visually placed. Any downstream edit could shift it. D introduces two problems: Grounding a component removes it from the assembly's motion hierarchy entirely, and a revolute As-Built Joint allows rotational freedom — the opposite of rigid. Neither behavior matches the requirement of a fixed, non-moving connection. A useful rule of thumb: whenever a question mentions components that are already in place and asks how to constrain them, think As-Built Joint first. Save regular Joints for situations where Fusion 360 needs to drive the positioning.

Question 2

An imported shaft is close to its intended location inside a bearing, but its axis is offset from the bearing axis and its shoulder is not seated against the bearing face. The finished assembly must permit only shaft rotation.

Which workflow correctly handles both the inaccurate placement and the required motion?

  1. Align the shaft to correct concentricity and seating, then create a revolute As-Built Joint. (correct answer)
  2. Create a revolute As-Built Joint first, expecting it to correct the offset and seating.
  3. Align the shaft to correct concentricity and seating, then ground both components separately.
  4. Create a rigid As-Built Joint first, then use Align to restore shaft rotation.
Explanation: When working with imported components in Fusion 360, you need to think in two distinct phases: geometric correction first, then joint definition. Joints capture the current positional relationship between components — they don't reposition parts for you. Understanding this separation is the key to answering assembly workflow questions correctly. The right approach, answer A, works because it respects this sequence. You first use Align (or Move/Copy) to correct the shaft's axis concentricity with the bearing bore and seat the shoulder flush against the bearing face. Once the geometry is accurate, you apply a revolute As-Built Joint, which locks in that corrected position and defines rotation as the only permitted degree of freedom. The result is a properly seated shaft that can only spin — exactly what the scenario requires. Answer B fails because an As-Built Joint freezes components as they currently sit, including the offset and gap. The revolute constraint won't pull the shaft into alignment; it will simply allow rotation around the wrong axis in the wrong position. Answer C gets the alignment step right but then goes completely wrong by grounding both components separately. Grounding eliminates all degrees of freedom for each part individually — no rotation, no motion of any kind. This contradicts the requirement that the shaft must rotate. Answer D reverses the logical order and compounds the problem. A rigid As-Built Joint locks everything including the misalignment, and rigid joints by definition prevent rotation. You cannot "restore" motion afterward with Align. Remember this rule: In Fusion 360, always align geometry before applying As-Built Joints — joints capture position, they don't correct it.

Question 3

In a design with design history enabled, a technician uses Move/Copy to place two components in their intended assembled positions. Fusion indicates that component positions have changed. The technician intends to create an As-Built Joint from this arrangement.

Which action best preserves the manually established layout in the timeline before the joint is defined?

  1. Choose Revert Position, then use the joint offset to reproduce the moved arrangement.
  2. Ground both components, create the joint, and unground both after the timeline updates.
  3. Choose Capture Position, then create the appropriate As-Built Joint between the components. (correct answer)
  4. Convert both components to bodies, capture the move, and recreate the components afterward.
Explanation: Whenever you see a question about joints and component positioning in Fusion 360 with design history enabled, focus on the timeline. Fusion 360 tracks parametric history, and when you manually move components, that positional change isn't automatically committed — Fusion flags it and asks what you want to do with it. The key workflow here is Capture Position. When Fusion detects that component positions have changed, choosing Capture Position records a snapshot of that arrangement as a timeline feature. This locks in the moved positions so that when you subsequently create an As-Built Joint — which joints components based on their current positions in the workspace — everything behaves predictably and the manual layout is preserved. That's exactly why C is correct. A sounds plausible but works against you. Reverting Position undoes your manual placement, returning components to their previous state. You'd then have to reconstruct the arrangement through joint offsets, which defeats the purpose of the manual layout you already established. B creates unnecessary complexity and introduces fragility. Grounding components freezes them in place temporarily, but it doesn't formally capture the positional history in the timeline. Ungrounding after the joint is created can also produce unexpected behavior if dependencies aren't resolved cleanly. D is destructive and disproportionate. Converting components to bodies strips away component-level structure — assemblies, joints, and hierarchies — just to preserve a position. This is never the right trade-off when Capture Position exists as a lightweight, non-destructive solution. Remember: in Fusion 360, Capture Position = commit the move to the timeline. Any time you manually reposition components and plan to joint afterward, Capture Position is your first step.

Question 4

A loose bracket must be aligned to a stationary frame before a rigid As-Built Joint is created. The bracket should move to the frame, not the frame to the bracket. The first alignment preview places the bracket on the wrong side of the target plane.

Which Align workflow best corrects the placement while keeping the frame stationary?

  1. Use bracket geometry as the source, frame geometry as the target, and apply Flip if required. (correct answer)
  2. Use frame geometry as the source, bracket geometry as the target, and apply Flip if required.
  3. Ground the bracket, use either component as the source, and rotate the frame after alignment.
  4. Create the rigid As-Built Joint first, then use Align to move the joined bracket independently.
Explanation: When working with the Align command in Fusion 360, the key principle to internalize is: the source moves, the target stays. Whichever component you select as the source geometry will be repositioned to match the target. Keeping this rule clear prevents accidental movement of components you want stationary. In this scenario, the bracket must move to the frame — meaning the bracket is the source and the frame is the target. When the initial alignment preview lands the bracket on the wrong side of the target plane, you simply toggle Flip to mirror the orientation without changing which component moves. This makes A the correct approach: bracket as source, frame as target, Flip applied as needed. B inverts the source/target relationship, which would move the frame instead of the bracket — exactly what the question tells you to avoid. This is a common trap because swapping source and target seems like a minor adjustment, but it reverses which component gets repositioned entirely. C introduces an unnecessary workaround. Grounding the bracket defeats the purpose — you want the bracket free to move. Rotating the frame afterward also violates the constraint that the frame must remain stationary. D gets the workflow backwards. Align is meant to prepare components for joint creation, not correct placement after a joint has already been established. Attempting to move one component of an existing rigid joint independently would either fail or break the joint's intent. Study tip: On Fusion 360 workflow questions, always identify which component should move first — that component is always your source. Let that determination drive every other choice.

Question 5

A pin is already positioned in a straight guide slot. During operation, the pin must translate along the slot and rotate about its own axis, but it must not move sideways out of the slot.

Which As-Built Joint type most closely represents the required motion?

  1. A cylindrical joint, which constrains both rotation and translation to the same single axis.
  2. A pin-slot joint, which allows pin rotation about its axis and translation along the slot direction. (correct answer)
  3. A planar joint, which allows two in-plane translations and one rotation normal to the plane.
  4. A revolute joint, which allows rotation about one axis while preventing all translation.
Explanation: When tackling joint-type questions in Fusion 360, focus on counting the degrees of freedom (DOF) the real-world scenario actually requires, then match that to the joint definition. In this scenario, the pin needs exactly two freedoms: rotation about its own axis AND translation along the slot direction — while everything else (sideways drift, tilting, lifting out) is locked. That precise combination is the definition of a pin-slot joint, making B the correct answer. It constrains four DOF while deliberately preserving those two specific motions along the same axis — perfect for a pin riding inside a linear guide. A describes a cylindrical joint, which also allows rotation and translation along the same axis — and you might think that sounds identical. The critical distinction is context and naming convention in Fusion 360: a cylindrical joint is used when the component is free-floating along a shared axis, not constrained within a physical slot geometry. The pin-slot joint explicitly models the slot constraint, keeping the pin from wandering laterally. C, the planar joint, gives you two translational DOF within a plane plus one rotational DOF perpendicular to it — three freedoms total, which is far too permissive. The pin could slide sideways out of the slot entirely. D, the revolute joint, allows only rotation — zero translation — which would weld the pin to one spot along the slot. That contradicts the requirement that it must also travel along the slot's length. A good study tip: memorize each joint by its DOF count and direction. The pin-slot joint's name is a direct clue — "pin" (rotation) plus "slot" (translation) — use that pairing as your memory anchor.

Question 6

A grounded mounting plate, a motor housing, and a rotor are separate components already positioned correctly. The housing must remain fixed to the plate, while the rotor must spin inside the housing without axial translation.

Which pair of As-Built Joints produces the intended assembly behavior?

  1. A rigid joint between rotor and housing, plus a revolute joint between housing and plate.
  2. A revolute joint between housing and plate, plus a slider joint between rotor and housing.
  3. A rigid joint between housing and plate, plus a revolute joint between rotor and housing. (correct answer)
  4. A rigid joint between housing and plate, plus a rigid joint between rotor and housing.
Explanation: When working with As-Built Joints in Fusion 360, your job is to match each relationship in the physical scenario to the joint type that controls exactly the right degrees of freedom — no more, no less. In this assembly, the housing must be completely locked to the grounded plate — no movement of any kind. A rigid joint eliminates all six degrees of freedom between two components, making them behave as a single fixed unit. The rotor, meanwhile, needs to spin freely inside the housing but cannot slide axially. A revolute joint allows exactly one degree of freedom: pure rotation around a single axis. It prevents translation in all directions while permitting that spin. That combination — rigid between housing and plate, revolute between rotor and housing — is precisely what answer C describes, making it correct. Answer A reverses the logic entirely. Placing a revolute joint between the housing and plate would allow the housing itself to rotate relative to the grounded plate, which violates the "fixed housing" requirement. The rigid joint on the rotor would then prevent it from spinning at all. Answer B compounds the error: the revolute joint is still in the wrong place (housing-to-plate), and a slider joint on the rotor would allow axial translation — exactly what the problem says to prevent. Answer D uses rigid joints on both connections, which locks the rotor completely. The rotor can't spin at all, defeating the entire purpose of the assembly. As a study strategy, always map each physical constraint to a joint type before looking at the answer choices: "fixed = rigid, spin only = revolute, slide only = slider." This prevents you from being misled by answer choices that use correct joint types in swapped locations.

Question 7

Two ungrounded components are correctly positioned and connected with a rigid As-Built Joint. When the designer drags one component, both components move together without changing their spacing or orientation.

What is the best explanation for this behavior?

  1. The rigid joint is defective because it should lock both components to the global origin.
  2. The rigid joint removes relative motion, but the connected pair remains free to move globally. (correct answer)
  3. The rigid joint temporarily behaves as a planar joint until one component is aligned.
  4. The rigid joint preserves spacing only, so orientation must be constrained by grounding both parts.
Explanation: When working with joints in Fusion 360, it helps to distinguish between relative constraints and global freedom. A joint defines how two components can move relative to each other — it says nothing about where those components sit in the overall design space. A rigid As-Built Joint removes all six degrees of relative freedom between two components — no translation, no rotation between them. Because of this, when you drag one component, the other follows perfectly, maintaining their exact spacing and orientation. This is precisely what answer B describes: the joint eliminates relative motion, but the connected pair, as a unit, remains free to move anywhere in global space since neither component is grounded. Answer A is wrong because joints are not meant to anchor components to the global origin — that is the job of grounding. Locking to the origin is a separate operation entirely. Answer C introduces the concept of a planar joint, which is a completely different joint type that allows sliding along a plane while restricting out-of-plane motion — a rigid joint never temporarily behaves this way. Answer D mischaracterizes what a rigid joint does: it constrains both spacing and orientation between the two parts simultaneously, not just spacing. The second part of D is also misleading — you ground components to fix them globally, not to define orientation between them. A useful rule of thumb: joints govern relative behavior; grounding governs global behavior. On questions about unexpected motion in assemblies, always ask two separate questions — "Are the parts constrained to each other?" and "Are the parts constrained to the world?"

Question 8

A designer uses Align to place the planar base of a purchased clamp against a workbench component. The clamp appears correctly positioned, but no joint has been created. The clamp must remain attached if components are later dragged during assembly testing.

What should the designer do next?

  1. Ground the clamp so its aligned position is fixed independently of the workbench.
  2. Capture the alignment as a new body so the clamp cannot move independently.
  3. Add a rigid As-Built Joint between the aligned clamp and workbench components. (correct answer)
  4. Add a slider As-Built Joint with its axis normal to the aligned faces.
Explanation: Whenever you see a question about positioning components in Fusion 360, distinguish between visual placement and kinematic constraint. The Align command moves components into position geometrically, but it does not create any joint — meaning the component is free to drift the moment anything in the assembly is manipulated. To lock that positioned relationship permanently, you need a joint. Because the components are already in their correct positions, an As-Built Joint is the right tool — it captures the current real-world position rather than asking you to re-specify geometry offsets. Choosing Rigid as the joint type means zero degrees of freedom: the clamp cannot translate or rotate relative to the workbench under any circumstances. That is exactly what the passage requires — the clamp must stay attached during assembly testing. C is therefore the correct answer. A is tempting but misleading. Grounding fixes a component to the world origin independently of everything else, which means if the workbench itself moves, the clamp would no longer follow it. Grounding is not the same as joining two components together. B is a fundamental misconception. Converting to a new body merges geometry — it does not constrain components within an assembly and actually destroys the component structure you need for assembly testing. D describes a slider joint, which intentionally allows linear motion along an axis. That is the opposite of what the scenario demands; you need zero movement, not controlled sliding. Your study tip: memorize that Align = position only, Joint = constraint. On assembly questions, always ask yourself whether the tool moves a component or connects it.

Question 9

A motor is a nested subassembly containing a housing and a rotor component. The housing is already mounted rigidly to a machine frame, and the rotor is correctly positioned inside the housing. The rotor must rotate while the rest of the motor remains stationary.

Which component selection is appropriate when creating the rotor's revolute As-Built Joint?

  1. Select the complete motor subassembly and the frame so the rotor inherits rotational motion.
  2. Select the housing and frame because their fixed relationship establishes the rotor axis.
  3. Select the rotor and frame so the motor housing is excluded from the relationship.
  4. Select the rotor occurrence and housing occurrence so only their relative motion is defined. (correct answer)
Explanation: When working with As-Built Joints in Fusion 360, your goal is to define motion between two specific components based on their current positions — not to describe the entire assembly hierarchy. The key question to ask yourself is: "Which two things are moving relative to each other, and what motion do I want to constrain?" In this scenario, the rotor needs to spin inside the housing. The relationship you want to define is purely between the rotor and the housing — the rotor rotates while the housing stays fixed. That makes D the correct choice. By selecting the rotor occurrence and the housing occurrence, you're telling Fusion 360 exactly which two components share this revolute relationship, and the joint axis is resolved from their current (as-built) positions. The housing acts as the stationary reference, and the rotor gets one rotational degree of freedom relative to it. A is wrong because selecting the entire motor subassembly lumps the rotor and housing together as one unit — the rotor can't rotate independently within something it's already grouped into. B is a subtle trap: the housing-to-frame relationship is already handled by the housing's rigid mount to the frame; redefining it here doesn't give the rotor any motion at all. C sounds tempting since the frame is stationary, but skipping the housing means you've bypassed the immediate parent context — the rotor's motion is defined relative to the housing, not the distant frame, which could introduce unexpected degrees of freedom or conflicts. As a study tip: always identify the two directly interacting components for any joint. Reaching past an intermediate component to grab a distant reference is a common mistake in nested subassembly scenarios.

Question 10

A shaft and bearing housing are already correctly coaxial and axially positioned. The shaft must rotate in the housing but must not slide along its axis.

Which As-Built Joint configuration provides the intended behavior?

  1. A cylindrical type using the shaft axis, allowing rotation and axial translation.
  2. A slider type using the shaft axis, allowing translation but preventing rotation.
  3. A rigid type located on the shaft axis, preventing translation and rotation.
  4. A revolute type using the shaft axis, allowing rotation but preventing translation. (correct answer)
Explanation: When working with joints in Fusion 360, the key distinction is between As-Built Joints (which constrain components already in position) and standard joints. The real challenge here is matching the mechanical requirement — rotation yes, axial sliding no — to the correct joint type. A revolute joint is built around a single rotational degree of freedom along a defined axis. It allows the shaft to spin freely inside the housing while locking out any translation along that same axis. This maps perfectly to the scenario: the shaft rotates but stays put axially. D is the correct answer. Here's why the other options fail: A (cylindrical) is close but too permissive — a cylindrical joint allows both rotation and axial translation simultaneously, so the shaft could slide out of the housing. That's one degree of freedom too many. B (slider) is essentially the opposite of what you need: it permits linear translation along the axis while preventing rotation, which would let the shaft slide but not spin — exactly backwards from the requirement. C (rigid) locks everything down completely, eliminating both rotation and translation. A rigid joint is useful for bonding components together permanently, but here it would prevent the shaft from rotating at all, defeating the entire purpose. A useful memory trick: think of joint names as describing what they allow. A revolute joint allows revolution (rotation). A slider allows sliding (translation). A cylindrical allows both. A rigid allows nothing. Map those definitions to your mechanical requirements before selecting a joint type, and these questions become straightforward.