Autodesk Fusion 360 Quiz: Shell And Draft

10 questions · exam conditions

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Shell And DraftQuestion 1 of 10

A designer needs a completely enclosed lightweight body with a uniform internal cavity. The body must not have an opening after the feature is created.

Which Shell workflow best meets this requirement?

Select the solid body in Shell without choosing any face to remove, then specify the wall thickness.

Select one exterior face in Shell to create an opening, then close it with a Patch feature.

Select every exterior face in Shell so that all faces are removed, leaving only the offset surfaces.

Select two opposite exterior faces in Shell and set matching thicknesses to close the gaps.

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Autodesk Fusion 360 Quiz

Autodesk Fusion 360 Quiz: Shell And Draft

Practice Shell And Draft 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 Shell And Draft, 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 needs a completely enclosed lightweight body with a uniform internal cavity. The body must not have an opening after the feature is created.

Which Shell workflow best meets this requirement?

Select the solid body in Shell without choosing any face to remove, then specify the wall thickness. (correct answer)
Select one exterior face in Shell to create an opening, then close it with a Patch feature.
Select every exterior face in Shell so that all faces are removed, leaving only the offset surfaces.
Select two opposite exterior faces in Shell and set matching thicknesses to close the gaps.

Explanation: When working with the Shell feature in Fusion 360, the key question to ask yourself is: what happens to the faces I select? Shell hollows out a solid body by offsetting its surfaces inward, and any face you explicitly select gets removed, creating an opening. If you select no faces at all, the tool simply offsets every surface inward uniformly, producing a completely enclosed hollow body — exactly what the passage describes. That's why A is correct. By activating Shell, selecting the solid body, and specifying a wall thickness without designating any face for removal, Fusion 360 creates a sealed, lightweight shell with a uniform internal cavity and no openings. B fails because it deliberately introduces an opening by selecting a face to remove, then requires a secondary Patch operation to close it. That's two steps solving a problem you created yourself — and it contradicts the requirement for no opening after the feature is created. C is a critical trap: selecting every exterior face tells Shell to remove all of them, leaving you with disconnected offset surfaces rather than a closed body. You'd end up with no enclosed cavity at all. D might sound logical — balancing thicknesses on opposite faces — but Shell doesn't work by pairing faces to "close gaps." Selecting two faces still removes those faces, leaving openings on both sides of the body. Wall thickness controls the offset depth, not whether a face is retained or removed. The study tip here: in Fusion 360's Shell feature, face selection = face removal. If you want a fully enclosed result, select no faces — just the body itself.

Question 2

A plastic enclosure requires tapered side walls and a uniform wall thickness measured normal to those walls. The current timeline creates an inward Shell first and then drafts only the exterior side faces.

What is the most appropriate timeline change?

Move Draft before Shell so the shell offsets the already tapered exterior faces. (correct answer)
Keep Shell before Draft and double the shell thickness on the exterior faces.
Move Draft after all features and draft only the interior side faces.
Replace Shell with an outward Draft applied to both exterior and interior faces.

Explanation: Whenever you see a question about feature order in Fusion 360, ask yourself: which geometry does each operation use as its reference? Shell and Draft both care deeply about the shape they see at the moment they execute in the timeline. Shell calculates wall thickness by offsetting surfaces normal to whatever faces exist at that point in time. Draft tilts faces by a specified angle relative to a pull direction. The critical insight is that if you Shell first on vertical walls and then Draft those walls, the shell thickness was measured perpendicular to vertical faces — but after drafting, the walls are now angled, so the actual material thickness normal to the finished tapered wall is no longer uniform. The geometry is subtly wrong. Option A fixes this by moving Draft before Shell. The exterior faces are tapered first, and then Shell offsets all surfaces — including those already-angled walls — normal to their final geometry. The result is a truly uniform wall thickness measured perpendicular to the tapered surfaces, which is exactly what injection-molded plastic enclosures require. Option B is wrong because simply doubling the shell thickness is a numerical guess that doesn't geometrically correct the non-uniform offset problem — it only compensates approximately for one draft angle, not universally. Option C is wrong because drafting only interior faces after shelling creates mismatched taper directions between inner and outer walls, producing variable thickness in the opposite way. Option D is wrong because replacing Shell entirely with Draft eliminates the hollow enclosure — Draft only tilts surfaces, it doesn't create wall thickness at all. Study tip: In Fusion 360, always think "what shape does this feature see when it runs?" — feature order controls geometric references, not just appearance.

Question 3

A rectangular block is $40\text{ mm}$ tall and $50\text{ mm}$ wide. Its base is the fixed plane. Both opposite side faces are drafted outward by $5^\circ$ , so the top becomes wider while the base width remains unchanged.

Approximately what is the resulting top width?

$53.5\text{ mm}$ because only one side face contributes to the total width increase.
$57.0\text{ mm}$ because both opposite side faces each contribute an outward displacement. (correct answer)
$52.6\text{ mm}$ because the width increases by the block height multiplied by the sine of the draft angle.
$60.0\text{ mm}$ because each side moves outward by a distance equal to the draft angle value in millimetres.

Explanation: When working with draft angles in Fusion 360, think of each drafted face as a tilted wall that leans outward by a given angle from vertical. The key formula for how much a face moves horizontally is:

\Delta w = h \times \tan(\theta)

where

h

is the height of the block and

\theta

is the draft angle. Here,

h = 40\text{ mm}

and

\theta = 5°

, so each side face displaces outward by:

\Delta w = 40 \times \tan(5°) \approx 40 \times 0.0875 \approx 3.50\text{ mm}

Since both opposite side faces draft outward, the total increase in width is

2 \times 3.50 = 7.0\text{ mm}

, making the top width approximately

50 + 7.0 = 57.0\text{ mm}

. That confirms B is correct. Choice A arrives at

53.5\text{ mm}

by correctly calculating one side's displacement but forgetting to account for the second face — a classic symmetry oversight. Choice C uses

\sin(5°) \approx 0.087

instead of

\tan(5°)

; while the values are close for small angles, sine measures the wrong component here — you need the horizontal run for a given vertical rise, which is tangent. Choice D treats the draft angle's numerical value (5) as a literal millimeter measurement per side, ignoring trigonometry entirely — a fundamental unit/concept confusion. Your study tip: whenever a draft is applied to two opposite faces, always double the per-face displacement. Also, drill the distinction between

\sin

\cos

, and

\tan

in geometric contexts — the exam frequently tests which ratio applies to which component.

Question 4

A molded component separates at an irregular parting edge around its middle. Faces above and below that edge must taper away in opposite directions relative to the mold-opening direction.

Which Draft setup most directly represents this manufacturing requirement?

Use Chamfer, selecting the parting edge and entering the required draft angle.
Use Fixed Plane draft, selecting one distant planar end as the neutral reference.
Use Shell, selecting the irregular middle faces as the openings to remove.
Use Parting Line draft, selecting the parting geometry and the mold pull direction. (correct answer)

Explanation: When working with draft angles in Fusion 360, you need to match the type of draft operation to the physical behavior of the mold. The key question to ask yourself is: "How does the parting geometry control the direction of taper on each side?" Parting Line draft is purpose-built for exactly this scenario. It lets you select an irregular, non-planar parting edge as the reference geometry, then specify a pull direction (the mold-opening axis). Fusion 360 automatically tapers faces above the parting line in one direction and faces below in the opposite direction — precisely what injection-molded parts separated at an irregular middle seam require. D is the correct answer because it directly maps to both constraints in the problem: an irregular parting edge and opposing draft directions. A is wrong because Chamfer creates a flat beveled edge between two faces — it's a geometry modification tool, not a draft angle tool. It has no concept of mold pull direction or face tapering. B describes Fixed Plane draft, which uses a single flat plane as the neutral reference; all drafted faces taper away from that plane uniformly. This works for simple parts but cannot handle an irregular, mid-body parting edge where opposite faces must taper in opposing directions. C describes Shell, which hollows out a solid by removing selected faces — completely unrelated to draft angles or mold separation. As a study tip, remember the Fusion 360 draft trio: Fixed Plane (simple flat neutral plane), Parting Line (irregular edge, opposing tapers), and From Edge (draft from a specific edge). Matching the tool to the parting geometry complexity is the core skill being tested here.

Question 5

A solid box must become a tray with both its top and one end open. The remaining exterior dimensions must stay unchanged, and all retained walls must have a uniform thickness.

Which setup should be used in a single Shell feature?

Select only the top face and use an outside shell thickness.
Select the top and end faces and use an inside shell thickness. (correct answer)
Select the top and bottom faces and use an inside shell thickness.
Select the entire body and use a centered shell thickness.

Explanation: When working with the Shell command in Fusion 360, you need to think about two things simultaneously: which faces to remove (open up) and which direction the shell thickness grows. The Shell tool hollows out a solid body by removing selected faces and offsetting the remaining walls inward, outward, or centered. For this tray, you need two open faces — the top and one end — while keeping all exterior dimensions unchanged. Selecting those two faces tells Fusion 360 to remove them entirely, leaving the remaining five walls intact. Using an inside shell thickness means the walls grow inward, so the outer boundary of the box stays exactly where it was. This is precisely what option B describes, making it the correct setup. Option A fails on two counts: selecting only the top face leaves the end wall solid rather than open, and an outside shell thickness would push the walls outward, enlarging the exterior footprint — violating the requirement that exterior dimensions stay unchanged. Option C selects the top and bottom faces, which would remove the floor of the tray. A tray without a bottom isn't a tray — it's a frame. The bottom wall must be retained, not opened. Option D misunderstands the Shell tool entirely. You cannot select an entire body as the face selection; the tool requires specific faces to remove. A centered thickness also splits wall growth both inward and outward, which would change the exterior dimensions. A useful rule of thumb: faces you select = faces that disappear, and inside thickness = exterior dimensions preserved. Keep those two principles paired together whenever a shell question specifies that outer dimensions must remain unchanged.

Question 6

A cylindrical boss must remain $20\text{ mm}$ in diameter where it meets a base plate, but its free end must be smaller to allow mold release. The pull direction is away from the plate.

Which Draft workflow best preserves the required boss diameter at the plate?

Use the plate face as the fixed plane and draft only the boss's flat end face along the pull direction.
Use the free-end face as the fixed plane and draft the cylindrical side outward toward the plate.
Use the cylindrical side face as the fixed plane and draft the plate face toward the boss axis.
Use the plate face as the fixed plane and draft the cylindrical side inward toward the free end. (correct answer)

Explanation: When working with Draft in Fusion 360, the critical concept is understanding which face acts as the fixed plane — the reference geometry that stays unchanged — and which faces receive the taper. The fixed plane never moves; everything else tilts relative to it. Here, your constraint is clear: the boss diameter at the plate must stay exactly

20\text{ mm}

. That means the base of the boss, where it meets the plate, cannot change. The taper must be applied upward toward the free end, making it smaller and allowing the part to release from the mold as the pull direction moves away from the plate. This is exactly what D accomplishes. By setting the plate face as the fixed plane, Fusion 360 anchors the boss-to-plate intersection at its current diameter. Drafting the cylindrical side inward toward the free end tapers the boss correctly — wider at the base, narrower at the top — without disturbing the

20\text{ mm}

requirement. A fails because drafting only the flat end face doesn't taper the cylindrical wall at all — it merely tilts the top cap, which does nothing for mold release on the side surface. B inverts the logic entirely: fixing the free end and drafting outward toward the plate would enlarge the base diameter, violating your constraint. C is nonsensical in practice — the cylindrical face itself cannot serve as a meaningful fixed plane for drafting that same face. As a study tip: always identify which dimension is constrained before choosing a fixed plane. The fixed plane protects that dimension; everything else moves.

Question 7

A housing is modeled as a solid rectangular box with outside dimensions $100\text{ mm} \times 60\text{ mm} \times 40\text{ mm}$ . The top face is removed with the Shell command, using an inside thickness of $3\text{ mm}$ . No other features are added.

Ignoring corner radii, what dimensions should the open top have after the shell is created?

$100\text{ mm} \times 60\text{ mm}$ because shelling does not alter the selected opening.
$97\text{ mm} \times 57\text{ mm}$ because one thickness is removed from each dimension.
$94\text{ mm} \times 54\text{ mm}$ because each dimension loses one thickness on both sides. (correct answer)
$106\text{ mm} \times 66\text{ mm}$ because the shell thickness is added around the opening.

Explanation: When working with Fusion 360's Shell command, you need to visualize what happens geometrically: the tool hollows out a solid body by removing material inward from all remaining faces by the specified thickness. The face you select to remove becomes the open face — but the walls surrounding that opening are built inward from the original exterior surfaces. Here's the key insight: the open top of the shell sits at the same level as the original top face, but its interior boundary is defined by the inner walls. Each of the four surrounding walls has a thickness of

3\text{ mm}

, and those walls eat into the opening from both sides along each dimension. So the open interior along the 100 mm length loses

3\text{ mm}

from the left wall and

3\text{ mm}

from the right wall, giving

100 - 6 = 94\text{ mm}

. The same logic applies to the 60 mm width:

60 - 6 = 54\text{ mm}

. This confirms C as correct. Choice A is a common trap — you might assume the selected face is left completely untouched, but the opening is bounded by the inner edges of the surrounding walls, not the outer edges. Choice B applies the thickness only once per dimension (subtracting

3\text{ mm}

instead of

6\text{ mm}

), which would be correct only if walls existed on just one side — a fundamental misunderstanding of how shelling works symmetrically. Choice D inverts the logic entirely, adding thickness outward rather than inward. As a study rule: whenever Shell is involved, always subtract twice the thickness from each dimension affected by two opposing walls.

Question 8

An inward Shell feature succeeds at $1.0\text{ mm}$ but fails at $2.0\text{ mm}$ . The solid contains a tight concave transition with a radius of approximately $1.5\text{ mm}$ . The selected opening face is otherwise valid.

Which change is most likely to make the $2.0\text{ mm}$ shell succeed while preserving the intended opening?

Increase the tight transition radius before applying the Shell feature. (correct answer)
Reverse the normal of the selected opening face before applying Shell.
Add a Draft feature to the opening face after applying the failed Shell.
Select additional opening faces so the wall offset becomes more uniform.

Explanation: When a Shell feature fails, your first instinct should be to ask: where does the offset geometry self-intersect or collapse? An inward shell offsets every wall surface toward the interior by the specified thickness. If the model contains a concave feature — a fillet, groove, or tight inside corner — whose radius is smaller than the shell thickness, the offset surface mathematically folds into itself, and Fusion 360 cannot resolve the result. That is exactly what is happening here: the

1.5\text{ mm}

concave transition radius allows a

1.0\text{ mm}

inward offset but collapses under a

2.0\text{ mm}

one (since

2.0 > 1.5

). The fix in A is correct because increasing that transition radius — say, to

2.5\text{ mm}

or larger — gives the offset surface enough room to propagate without self-intersecting. The shell engine can then complete the

2.0\text{ mm}

wall successfully, and the opening face remains unchanged. B is wrong because face normals govern which side of a surface is "outside," but reversing them does not change the underlying geometry or relieve the tight radius that causes the failure. C is wrong because Draft angles the opening face for mold release — it has no effect on the internal concave transition, and you cannot apply it after a feature that already failed. D is wrong because selecting more opening faces changes which faces are removed but does not alter the tight concave geometry causing the self-intersection. As a study tip: whenever a shell fails at thickness t, look for any concave radius smaller than t — that's almost always the culprit.

Question 9

A molded block is drafted using the Fixed Plane draft type. Its bottom planar face is selected as the fixed plane, and the four vertical side faces are selected as the faces to draft.

Which part of the model should remain dimensionally anchored as the draft angle is edited?

The side-face boundaries where the drafted faces meet the fixed bottom plane. (correct answer)
The side-face boundaries at the top, opposite the selected fixed plane.
The midpoint of every drafted face, regardless of the selected fixed plane.
The complete side faces, because Draft changes only their surface normals.

Explanation: When working with Fusion 360's Draft tool, the key concept to understand is what "Fixed Plane" actually means mechanically: it defines the geometric anchor — the location on the model that stays locked in space while the surrounding faces rotate outward or inward to create the draft angle. Think of it like pressing a stamp into clay; the surface touching the stamp doesn't move, but the sides splay outward. In this scenario, the bottom face is the fixed plane. This means the edges where the four vertical side faces intersect that bottom plane are the anchored boundaries — they don't shift position as you increase or decrease the draft angle. The faces pivot about those bottom edges, so A is correct. This is exactly how molded and cast parts are designed: the parting-line or base geometry stays precise, and the walls angle away from it. Choice B describes the opposite behavior — anchoring the top edges — which would correspond to a "Fixed Edge" approach anchored at the top, not the bottom plane you selected. Choice C is a fabrication; Fusion 360's Draft tool has no mid-face anchoring behavior. Choice D misrepresents the tool entirely — Draft absolutely moves face geometry (vertices and edges shift in 3D space); it doesn't merely adjust surface normals the way a normal-map texture would. A useful study tip: whenever a question mentions "Fixed Plane" in Fusion 360's Draft command, immediately visualize which plane was selected — that plane's intersection with the drafted faces is always the stationary boundary. The faces rotate about those shared edges, not anywhere else.

Question 10

A Fixed Plane Draft feature produces the correct taper. The designer then reverses the pull direction, and the preview shows the taper facing the opposite way. The final geometry must remain as it was before the pull direction was reversed.

Which additional edit is most likely to restore the original taper?

Replace the fixed plane with a plane parallel to the drafted faces.
Double the draft angle while retaining its current direction.
Reverse the sign or direction of the draft angle as well. (correct answer)
Change the feature to Shell while retaining the same angular value.

Explanation: Whenever you encounter a Draft feature question in Fusion 360, think about the relationship between pull direction and draft angle sign — they work as a pair. A Fixed Plane Draft tilts faces relative to a fixed plane, and the direction of that taper is jointly determined by both the pull direction vector and the sign of the draft angle. If you flip one without adjusting the other, the geometry inverts. Here's the core logic: reversing the pull direction is mathematically equivalent to negating it. To preserve the original taper geometry, you need to counteract that negation — which means also reversing the draft angle's sign or direction. The two reversals cancel each other out, restoring the original result. That's exactly what C describes, making it the correct answer. A is wrong because replacing the fixed plane with a parallel plane doesn't address the directional relationship at all — a parallel plane produces the same geometric reference, so the taper remains inverted. B is a trap for students who confuse magnitude with direction. Doubling the angle changes how much taper is applied, not which way it faces. You'd end up with a larger inverted taper, not the original one. D is a completely different feature type. Shell hollows out a solid body — it has nothing to do with draft angles or correcting taper direction. As a study tip, remember this pairing rule: pull direction and draft angle sign are a matched set. If you change one to achieve a specific geometry, changing the other restores it. Exam questions often test whether you understand this compensatory relationship.