Autodesk Fusion 360 Quiz: Motion Study
10 questions · exam conditions
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Motion StudyQuestion 1 of 10

A designer creates a revolute joint between a crank and a frame, then uses Drive Joint. The crank rotates as expected, but the frame also changes position relative to the design origin. No component in the assembly is grounded.

What should the designer do before using Drive Joint again to obtain a meaningful assembly-behavior test?

Ground the frame component and retain the revolute joint between the frame and crank.
Ground the crank component and suppress the revolute joint connecting it to the frame.
Create a rigid group containing the frame and crank, then drive the existing revolute joint.
Capture the current frame position and replace the revolute joint with a contact set.
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Autodesk Fusion 360 Quiz

Autodesk Fusion 360 Quiz: Motion Study

Practice Motion Study 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 Motion Study, 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 designer creates a revolute joint between a crank and a frame, then uses Drive Joint. The crank rotates as expected, but the frame also changes position relative to the design origin. No component in the assembly is grounded.

What should the designer do before using Drive Joint again to obtain a meaningful assembly-behavior test?

  1. Ground the frame component and retain the revolute joint between the frame and crank. (correct answer)
  2. Ground the crank component and suppress the revolute joint connecting it to the frame.
  3. Create a rigid group containing the frame and crank, then drive the existing revolute joint.
  4. Capture the current frame position and replace the revolute joint with a contact set.
Explanation: When working with joints and motion in Fusion 360, the key concept to understand is degrees of freedom (DOF). Every component in an assembly can move freely unless its motion is constrained. When no component is grounded, driving a joint produces relative motion between connected parts — but because nothing is anchored to the world, the entire assembly can drift, making your simulation meaningless. Grounding the frame is the correct fix (A). By grounding the frame, you pin it to the design origin with zero DOF, so it cannot translate or rotate in world space. The revolute joint then constrains the crank relative to the stationary frame, and driving that joint produces exactly the motion you want to analyze — the crank spinning predictably while the frame stays put. Option B is backwards: grounding the crank and suppressing the joint defeats the purpose entirely. You want to observe the crank's rotation, not freeze it. Suppressing the joint removes the very relationship you're trying to drive. Option C is a common trap. A rigid group locks components together into a single body, eliminating relative motion between them. This would prevent the crank from rotating relative to the frame, which is the opposite of your goal. Option D introduces a contact set, which governs collision behavior rather than position. Replacing a revolute joint with a contact set doesn't anchor anything to the origin and doesn't solve the floating-assembly problem. Study tip: On Fusion 360 assembly questions, always ask "what is grounded?" before analyzing joint behavior. If nothing is grounded, driven joints produce undefined, floating results — ground your reference component first.

Question 2

A hinged cover is connected to its housing by a revolute joint. A motion study rotates the cover through its full specified range, but the cover visibly passes through a latch component. The revolute joint and its limits are otherwise correct.

Which change most directly tests whether physical contact with the latch should stop the cover?

  1. Increase the number of positions in the motion study without changing the component relationships.
  2. Replace the revolute joint with a rigid joint and replay the same angular sequence.
  3. Apply a contact relationship to the relevant components and enable contact during the motion test. (correct answer)
  4. Ground both the cover and latch before driving the existing revolute joint through its limits.
Explanation: When troubleshooting interpenetration (components passing through each other) in Fusion 360 motion studies, the key distinction is between kinematic behavior and physical behavior. A motion study by default drives joints through their specified ranges mathematically — it has no awareness of geometry collisions unless you explicitly tell it to detect them. This is exactly why C is correct. Applying a contact relationship between the cover and latch, then enabling contact during the motion test, instructs Fusion 360 to treat those surfaces as physically solid. If the cover's geometry actually reaches the latch before hitting the joint limit, contact will stop it there — directly testing whether the latch acts as a real mechanical stop. This is the only change that addresses the root issue: the simulation ignoring geometry. Choice A simply adds more snapshot positions to the study. More positions means finer resolution, but the cover will still pass through the latch at every one of them — you've changed sampling density, not collision behavior. Choice B replaces the revolute joint with a rigid joint, which locks the component in place entirely. You can't replay an angular sequence on a rigid joint, so this contradicts the test scenario and defeats the purpose of the motion study. Choice D grounds both the cover and the latch, which would prevent any motion at all. Grounding fixes components to the world frame — you cannot drive a grounded component through a joint range, so the test becomes impossible to run. As a study tip: whenever a Fusion 360 question involves components passing through each other, the answer almost always involves contact sets — that's the feature specifically designed to enforce geometric collision during simulation.

Question 3

Two shaft components are connected by revolute joints to a grounded housing. A motion link is defined so that shaft B rotates in the opposite direction at one-third of shaft A's angular displacement. The relationship is therefore θB=−13θA\theta_B=-\frac{1}{3}\theta_A.

If Drive Joint rotates shaft A from 0∘0^\circ to +90∘+90^\circ, what result should indicate that the linked assembly behavior is correct?

  1. Shaft B rotates to +30∘+30^\circ because only the magnitude of the motion ratio is applied.
  2. Shaft B rotates to −90∘-90^\circ because linked revolute joints must have equal displacement.
  3. Shaft B rotates to +270∘+270^\circ because the driven shaft uses the reciprocal relationship.
  4. Shaft B rotates to −30∘-30^\circ because both the ratio and opposite direction are applied. (correct answer)
Explanation: When working with motion links in Fusion 360, you need to apply the complete mathematical relationship — both the magnitude of the ratio and any sign (direction) embedded in it. The motion link formula θB=−13θA\theta_B = -\frac{1}{3}\theta_A tells you two things simultaneously: shaft B moves at one-third the displacement of shaft A, and it moves in the opposite direction (indicated by the negative sign). Plugging in θA=+90∘\theta_A = +90^\circ: θB=−13(90∘)=−30∘\theta_B = -\frac{1}{3}(90^\circ) = -30^\circ This confirms D is correct — shaft B rotates to −30∘-30^\circ, honoring both the scalar ratio and the directional inversion. A is wrong because it applies only the magnitude (13×90∘=+30∘\frac{1}{3} \times 90^\circ = +30^\circ) while ignoring the negative sign. Dropping the sign is a classic trap — it changes the physical behavior of the assembly entirely. B is wrong because it assumes revolute joints linked by a motion link must share equal displacement. Motion links exist precisely to define custom ratios between joints; −90∘-90^\circ would only result if the ratio were −1-1. C is wrong because it inverts the ratio incorrectly, using 33 instead of 13\frac{1}{3}, giving +270∘+270^\circ. The reciprocal relationship does not apply here — the defined formula is what governs the driven shaft. When you see a motion link formula in Fusion 360 questions, always treat the entire expression — coefficient and sign — as your calculation rule. Never strip the sign away; it encodes real-world direction.

Question 4

A revolute joint has enabled limits of −40∘-40^\circ and +70∘+70^\circ. A designer must test a sweep from −60∘-60^\circ to +60∘+60^\circ using Drive Joint.

What must be changed before the complete required sweep can be tested while retaining meaningful joint constraints?

  1. Edit the lower joint limit to at least −60∘-60^\circ and keep the upper limit at or above +60∘+60^\circ. (correct answer)
  2. Edit the upper joint limit to +120∘+120^\circ while leaving the lower limit at −40∘-40^\circ.
  3. Offset the joint origin by 20∘20^\circ without changing either of the enabled angular limits.
  4. Disable the revolute joint and rotate the component freely between the two required endpoints.
Explanation: When working with Drive Joint in Fusion 360, think of joint limits as a "fence" that physically constrains motion. If you try to drive a joint beyond its enabled limits, Fusion 360 will stop the motion at the boundary — meaning your animation or test sweep gets cut short. The question here is really asking: what's the minimum change needed to allow the full −60°-60° to +60°+60° sweep while keeping the joint's constraints intact and meaningful? The current limits are −40°-40° (lower) and +70°+70° (upper). The required sweep needs to reach −60°-60° on the lower end and +60°+60° on the upper end. Since −60°<−40°-60° < -40°, the lower limit is too restrictive and must be expanded to at least −60°-60°. The upper limit of +70°+70° already covers +60°+60°, so it only needs to stay at or above +60°+60°. Choice A correctly identifies exactly this — adjusting the lower limit while leaving the upper limit valid. This is the precise, targeted fix. Choice B raises the upper limit to +120°+120°, which is unnecessary overkill and doesn't fix the actual problem: the lower limit of −40°-40° still blocks motion to −60°-60°. Choice C suggests offsetting the joint origin by 20°20°, which would shift the entire limit range but doesn't cleanly solve both boundary conditions simultaneously — and misrepresents how joint origins interact with angular limits in Fusion 360. Choice D disables the joint entirely, which removes all constraints and defeats the purpose of having a revolute joint with meaningful limits. As a study tip, always check both limits independently against your required range — each boundary is its own potential blocker.

Question 5

A door and frame are already positioned correctly in an imported assembly. The designer must preserve their current placement while defining hinge rotation, then use Drive Joint to test opening behavior.

Which approach is most appropriate?

  1. Create an as-built revolute joint using the existing component positions, then drive the resulting hinge joint. (correct answer)
  2. Create an as-built rigid joint at the hinge axis, then rotate the door with component dragging.
  3. Move both components to the origin, create a rigid group, and drive the group's angular position.
  4. Capture the current position, remove all assembly relationships, and animate the door transform directly.
Explanation: When working with imported assemblies in Fusion 360, the critical challenge is preserving component positions that already look correct while still adding motion behavior. This question tests your understanding of as-built joints versus standard joints, and when each is appropriate. The key insight is that standard joints in Fusion 360 reposition components to satisfy the joint's geometry — which would disturb your already-correct placement. As-built joints, by contrast, define the relationship based on where components currently sit, locking in their existing positions while still establishing the motion type. Answer A is correct because an as-built revolute joint captures the door and frame exactly where they are and defines a rotation axis without moving anything. Once that joint exists, Drive Joint lets you animate the hinge rotation to test opening behavior — exactly what the scenario requires. Answer B fails because a rigid joint eliminates all relative motion between the components, making it impossible to rotate the door afterward. Dragging a component doesn't respect joint-defined motion paths either. Answer C is doubly wrong: moving components to the origin defeats the entire purpose of preserving their current placement, and a rigid group prevents the very rotation you need to test. Answer D describes a destructive workflow — removing assembly relationships and animating raw transforms is not how Fusion 360's joint-driven motion system works, and it discards any structured kinematic behavior. Your study tip: whenever a question mentions components that are already positioned correctly and need motion added, think as-built joint immediately. It's Fusion 360's specific tool for this exact scenario.

Question 6

A camshaft and support bracket were accidentally connected with a rigid joint. When the designer attempts to use Drive Joint, no rotational range is available, although the shaft should rotate about a single fixed axis.

Which correction best prepares this assembly for the intended motion test?

  1. Keep the rigid joint and add a rigid group containing only the camshaft and support bracket.
  2. Replace the rigid joint with a revolute joint aligned to the shaft axis, then drive that joint. (correct answer)
  3. Replace the rigid joint with a planar joint located on the end face, then drive its translation.
  4. Suppress the rigid joint and rely on contact between the shaft and bracket to define rotation.
Explanation: Whenever you see a joint-type mismatch in Fusion 360, ask yourself: "What degrees of freedom does the intended motion actually require?" A rigid joint locks all six degrees of freedom — translation and rotation in every direction — which is exactly why Drive Joint offers nothing to work with. The joint type must match the physical motion before you can animate or test it. A revolute joint is precisely designed for rotation about a single fixed axis, which is what a camshaft needs. By replacing the rigid joint with a revolute joint aligned to the shaft's centerline, you restore the one rotational degree of freedom the assembly requires. Drive Joint can then sweep that joint through its angular range, making B the correct fix. Choice A fails because adding a rigid group containing those same components only reinforces the lock — a rigid group prevents relative motion between its members, doubling down on the problem rather than solving it. Choice C introduces a planar joint, which permits two translational axes and one rotation about the normal to the plane; this is wrong for a shaft that must spin about a single fixed axis without sliding. Driving its translation would move the shaft linearly, which is the opposite of the desired rotational test. Choice D is dangerous: suppressing the joint and relying on contact sets to define rotation is unreliable in Fusion 360's motion study environment and does not produce a clean, drivable rotational DOF. As a study tip, memorize the six standard joint types (rigid, revolute, slider, cylindrical, pin-slot, planar, ball) and the exact degrees of freedom each one permits — exam questions frequently test whether you can match a physical motion description to the correct joint type.

Question 7

A packaging mechanism completes a motion study without joint errors or visible component overlap. The study uses a grounded base, defined joints, joint limits, and the intended motion links. No force, torque, material, or load data were evaluated.

Which conclusion is best supported by this result?

  1. The mechanism will operate at the specified speed because successful playback verifies motor performance.
  2. The mechanism can follow the modeled kinematic sequence within the tested joint relationships and limits. (correct answer)
  3. The mechanism will withstand operating loads because the study verifies stresses at every joint position.
  4. The mechanism cannot collide in service because playback proves clearance under every possible condition.
Explanation: When evaluating what a motion study actually proves, you need to carefully distinguish between kinematic analysis and dynamic or structural analysis. Fusion 360 motion studies simulate how components move through a defined sequence — they check whether joints are properly constrained and whether the geometry physically fits through each position. They do not calculate forces, stresses, torques, or material responses. That distinction makes B the correct conclusion. The study confirmed that the mechanism can follow the modeled kinematic sequence within the tested joint relationships and limits — nothing more, nothing less. The passage explicitly states no force, torque, material, or load data were evaluated, which perfectly aligns with B's carefully scoped claim. A is wrong because successful playback says nothing about motor performance or operating speed. Speed and torque requirements require dynamic analysis, not a kinematic simulation. C is wrong because withstanding operating loads demands stress analysis (such as FEA), which was never performed — a clean playback cannot verify structural integrity at any joint position, let alone every one. D is tempting but dangerously overstated. The study shows clearance under the modeled conditions, but it cannot prove zero collisions under every possible service condition, which includes variations in alignment, manufacturing tolerances, and dynamic deflection not captured in a rigid-body motion study. A useful strategy: on questions involving simulation results, always ask what type of analysis was performed and match conclusions only to what that analysis is capable of proving. Kinematic studies prove motion feasibility — not strength, not speed, not real-world collision immunity.

Question 8

A slider joint is correctly aligned, but its positive axis points opposite the machine's intended extension direction. In Drive Joint, entering +25 mm+25\text{ mm} retracts the carriage by 25 mm25\text{ mm}. The joint otherwise behaves correctly.

What is the least disruptive way to test a 25 mm25\text{ mm} extension without rebuilding the assembly?

  1. Convert the slider joint to a rigid joint and apply a 25 mm25\text{ mm} component translation.
  2. Enter +50 mm+50\text{ mm} in Drive Joint so the carriage passes through zero and extends by the remainder.
  3. Ground the carriage and enter +25 mm+25\text{ mm} so the frame moves in the extension direction.
  4. Enter −25 mm-25\text{ mm} in Drive Joint because the desired movement is opposite the joint's positive axis. (correct answer)
Explanation: Whenever you see a question about joint behavior in Fusion 360, focus on the relationship between the joint's defined positive axis and the real-world direction of motion. A slider joint's Drive Joint input moves the component along that axis — positive values move in the positive axis direction, negative values move opposite it. If the axis is flipped relative to your intended direction, the fix is simply to input a negative value, not to restructure the joint. Here, the joint's positive axis points opposite the extension direction, meaning extension is the negative axis direction. To drive the carriage 25 mm25\text{ mm} in extension, you enter −25 mm-25\text{ mm}, which moves it exactly that distance along the negative axis — the extension direction. That makes D the correct and least disruptive solution: one number change, no assembly modifications. A is unnecessarily destructive. Converting to a rigid joint eliminates the slider's motion entirely, and a component translation bypasses joint-driven motion, breaking the parametric relationship you'd want to test. B contains a fundamental math error — entering +50 mm+50\text{ mm} when the joint retracts at positive values would retract the carriage by 50 mm50\text{ mm}, not pass through zero and extend. The joint has no implicit "bounce" behavior at zero. C misunderstands grounding — grounding the carriage would fix it in space and force the frame to move, which inverts your reference frame and doesn't simulate the intended mechanism behavior. As a study tip: when a joint axis is reversed, always reach for a sign change in Drive Joint first. It's the fastest, most reversible fix — and that's exactly the kind of minimal-disruption solution Fusion 360 exam questions reward.

Question 9

An assembly contains a revolute crank joint and a slider joint. During the required operating cycle, the crank must rotate first while the slider remains stationary. The slider must then extend during the final portion of the crank rotation.

Which workflow is most appropriate for testing this coordinated sequence in Fusion?

  1. Drive each joint separately in two previews and treat the previews as one coordinated operating cycle.
  2. Create a motion study and assign joint positions at multiple points so the slider initially remains fixed. (correct answer)
  3. Rigid-group the crank and slider, then animate the rigid group through the complete operating cycle.
  4. Delete the slider joint and use component dragging while the revolute joint is being driven.
Explanation: When testing coordinated, time-dependent motion between multiple joints in Fusion 360, you should immediately think about motion studies — Fusion's dedicated tool for scripting how joints behave across a timeline. The core challenge here is sequencing: the crank moves first, the slider stays still, then both operate together. That kind of phased coordination requires explicit control over each joint's position at specific moments in time. Motion studies let you set keyframes (joint position values at defined time points), which is exactly what makes B the correct approach. You assign the slider a fixed position during the crank's initial rotation phase, then introduce slider movement only during the overlapping final phase. This mirrors real-world machine timing and produces a single, reviewable animation of the full cycle — no guesswork about whether the sequence is accurate. A is flawed because running two separate previews and mentally stitching them together provides no actual coordinated simulation. You can't verify overlap, timing, or interaction between the two joints this way — it's a workaround, not a test. C is wrong because rigid-grouping the crank and slider locks them into a fixed spatial relationship, eliminating the independent motion that defines the whole scenario. You'd be animating them as one body, which defeats the purpose entirely. D destroys the slider joint altogether, removing the very degree of freedom you need to test. Dragging components manually is not a controlled or repeatable simulation method. The study tip here: whenever a question describes phased or sequenced joint motion, your default answer in Fusion 360 should involve motion studies with keyframed joint positions — that's the purpose they were built for.

Question 10

A linkage forms a closed loop using four revolute joints. An additional rigid joint was added between two links to hold an assembly position temporarily. Drive Joint now fails to move the input crank, even though each revolute joint is aligned correctly.

What is the most effective first diagnostic action?

  1. Increase the drive angle so the input crank has enough displacement to overcome the rigid relationship and move the loop.
  2. Add contact sets at every revolute connection so the solver can determine the missing degree of freedom.
  3. Temporarily suppress the added rigid joint, then drive the crank to check whether an overconstraint is blocking motion. (correct answer)
  4. Ground every link except the input crank, then replay the same Drive Joint operation to isolate the problem.
Explanation: Whenever you encounter a motion study or Drive Joint failure in Fusion 360, your first instinct should be to think about degrees of freedom and constraints. A four-bar linkage (four links, four revolute joints) already forms a closed-loop mechanism with exactly one degree of freedom. Adding a rigid joint on top of that eliminates the remaining degree of freedom entirely — the assembly becomes overconstrained, and the solver simply cannot move anything. This is precisely why C is correct. Suppressing the rigid joint temporarily restores the single degree of freedom the closed loop needs, letting you drive the crank and confirm the revolute joints are working correctly. If motion succeeds after suppression, you've isolated the culprit: the rigid joint was overconstrained the mechanism. This is the fastest, most targeted diagnostic step because it directly tests your hypothesis without changing the fundamental structure of the model. A misunderstands the problem. Increasing the drive angle doesn't help — an overconstrained system won't move regardless of how large the input displacement is. There's no "threshold" to overcome with more angle. B is counterproductive; adding contact sets introduces new constraints rather than removing the offending one, making the solver's job harder and the overconstraint worse. D grounds additional links, which would further restrict motion and obscure whether the rigid joint is the true source of failure — you'd be adding constraints on top of an already over-constrained system. Study tip: In Fusion 360 motion problems, always count constraints before diagnosing. When Drive Joint fails unexpectedly, your first move should be to suppress recently added joints one at a time — isolate before you modify.