AutoCAD Quiz: Polygons And Splines

10 questions · exam conditions

0:00

Polygons And SplinesQuestion 1 of 10

A fabricator needs a regular hexagonal plate whose six sides are tangent to a circular clearance boundary with radius $40\text{ mm}$ . The polygon and circle share the same center.

Which POLYGON workflow creates the required plate, and what is its approximate distance across opposite vertices?

Choose Circumscribed about circle, enter radius

40\text{ mm}

; the sides become tangent to the circle, producing about

92.38\text{ mm}

across opposite vertices.

Choose Inscribed in circle, enter radius

40\text{ mm}

; the vertices land on the circle, producing exactly

80.00\text{ mm}

across opposite vertices.

Choose Circumscribed about circle, enter radius

46.19\text{ mm}

; this treats the circumradius as the apothem, producing about

106.67\text{ mm}

across opposite vertices.

Choose Inscribed in circle, enter radius

46.19\text{ mm}

; the vertices land on that larger circle, producing about

92.38\text{ mm}

across opposite vertices.

← Back to quizzes

AutoCAD Quiz

AutoCAD Quiz: Polygons And Splines

Practice Polygons And Splines in AutoCAD 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 Polygons And Splines, giving you a quick way to practice the rules, question types, and explanations that matter most for AutoCAD.

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 fabricator needs a regular hexagonal plate whose six sides are tangent to a circular clearance boundary with radius $40\text{ mm}$ . The polygon and circle share the same center.

Which POLYGON workflow creates the required plate, and what is its approximate distance across opposite vertices?

Choose Circumscribed about circle, enter radius $40\text{ mm}$ ; the sides become tangent to the circle, producing about $92.38\text{ mm}$ across opposite vertices. (correct answer)
Choose Inscribed in circle, enter radius $40\text{ mm}$ ; the vertices land on the circle, producing exactly $80.00\text{ mm}$ across opposite vertices.
Choose Circumscribed about circle, enter radius $46.19\text{ mm}$ ; this treats the circumradius as the apothem, producing about $106.67\text{ mm}$ across opposite vertices.
Choose Inscribed in circle, enter radius $46.19\text{ mm}$ ; the vertices land on that larger circle, producing about $92.38\text{ mm}$ across opposite vertices.

Explanation: When working with AutoCAD's POLYGON command, the critical distinction is between two radius definitions: Inscribed in circle places vertices on the reference circle, while Circumscribed about circle places the midpoints of the sides on the reference circle — meaning the sides are tangent to it. This is exactly the geometry the fabricator needs. Since the problem requires the six sides to be tangent to a 40 mm radius boundary, you must choose Circumscribed about circle and enter

r = 40\text{ mm}

. For a regular hexagon, the relationship between the circumradius

R

(vertex-to-center) and the apothem

a

(side-midpoint-to-center) is

a = R \cdot \cos(30°)

, which rearranges to

R = \frac{a}{\cos(30°)} = \frac{40}{0.866} \approx 46.19\text{ mm}

. The distance across opposite vertices is

2R \approx 92.38\text{ mm}

. This confirms answer A is correct. Answer B fails because Inscribed in circle places the vertices on the 40 mm circle, making the sides chord inward — the sides never touch the clearance boundary, so the plate would be too small and would not respect the tangency requirement. Answer C is a procedural mix-up: entering

46.19\text{ mm}

into Circumscribed mode treats that value as the apothem, producing an even larger hexagon than needed — roughly

106.67\text{ mm}

across vertices. Answer D uses Inscribed mode with

46.19\text{ mm}

, which does yield vertices at

92.38\text{ mm}

apart, but this is the wrong workflow for the fabricator's intent; it reaches the right vertex distance by accident, not by enforcing side tangency. Study tip: Always map the geometric constraint to the correct radius type — if the spec mentions tangency to a circle, that's the apothem, so reach for Circumscribed.

Question 2

A designer creates an $8$ -sided object with POLYGON. Later, one vertex is moved outward using a vertex grip while all other vertices remain fixed.

What is the resulting object state immediately after the grip edit?

It remains one closed polyline, but it is no longer guaranteed to be a regular polygon with equal sides and angles. (correct answer)
It remains a regular polygon because AutoCAD automatically moves the other seven vertices to preserve equal side lengths.
It becomes an open polyline because moving any polygon vertex automatically breaks the closing segment at that vertex.
It becomes eight separate line objects because vertex editing automatically explodes objects created by the POLYGON command.

Explanation: When working with AutoCAD's POLYGON command, it helps to understand what type of object is actually created. POLYGON produces a closed polyline — not a special "polygon object" with protected geometry. This means it behaves exactly like any other polyline you might draw manually. Because it's a standard closed polyline, you can grip-edit any individual vertex freely. When you drag one vertex outward, AutoCAD simply repositions that single point. The two segments connected to it stretch to meet the new location, while all other vertices and segments stay exactly where they are. The object remains one continuous closed polyline — but the equal side lengths and angles that made it a regular polygon are now gone. That makes A correct. B is wrong because AutoCAD has no mechanism to automatically redistribute or adjust the other seven vertices to "rebalance" the shape. There is no parametric constraint preserving regularity unless you explicitly add geometric constraints yourself. C is wrong because moving a vertex does not break the closing segment or open the polyline — the polyline's closure is a property of the object, not dependent on vertex positions. All segments, including the closing one, simply adjust their endpoints. D is wrong because grip editing never explodes a polyline into individual line objects. Exploding is a separate, deliberate operation (the EXPLODE command); a simple grip edit preserves the object type entirely. A useful rule of thumb: POLYGON creates a regular polyline at the moment of creation, but grants no ongoing protection. Once drawn, it's just a polyline — editable like any other.

Question 3

A spline is created by the Fit method through measured locations, but the fit tolerance is set to $2\text{ mm}$ . Inspection shows that the curve does not pass through every entered location exactly, although no deviation exceeds $2\text{ mm}$ .

Which interpretation of this result is correct?

The result indicates that the spline was converted to a polyline whose vertices are spaced at $2\text{ mm}$ intervals.
The result indicates failure because fit points must always lie exactly on a spline regardless of the tolerance setting.
The result is expected because the value controls endpoint tangency, allowing up to $2\text{ mm}$ of tangent-direction error.
The result is expected because a positive fit tolerance permits the spline to deviate from each fit point within the specified distance. (correct answer)

Explanation: When working with splines in AutoCAD, you need to understand how the Fit method and fit tolerance interact. The Fit method creates a spline by passing through a set of user-specified fit points — but the fit tolerance value changes exactly how strictly "through" means. A fit tolerance of

0

forces the spline to pass precisely through every fit point. When you enter a positive value like

2\text{ mm}

, you're telling AutoCAD that the spline is permitted to deviate from each fit point by up to that distance. The software uses this flexibility to produce a smoother, mathematically cleaner curve. So a spline that stays within

2\text{ mm}

of every point — but doesn't hit them exactly — is behaving exactly as designed. That makes D the correct interpretation. A is incorrect because fit tolerance has nothing to do with converting splines to polylines or spacing vertices at intervals. That describes a completely different operation (like SPLINEDIT's conversion function). B is wrong because it reverses the actual rule — fit points must lie exactly on the spline only when the tolerance is

0

. A nonzero tolerance explicitly relaxes that requirement, so deviations are not a failure. C is a fabricated concept; fit tolerance does not control endpoint tangency direction. Tangency is a separate property managed through tangent handles, not the tolerance value. As a study tip, remember this pairing: tolerance = $0$ means exact passage; tolerance $> 0$ means allowable deviation. AutoCAD exam questions often test whether you know that "fit" doesn't always mean "touching" — the tolerance value is the deciding factor.

Question 4

A fit-point spline uses tolerance $0$ . Without moving or adding any fit points, the drafter changes its knot parameterization from Chord to Uniform.

What is the most likely effect of this edit?

The spline degree automatically changes to $1$ , turning the object into connected straight segments.
The fit points become control vertices, so the curve generally stops passing through the interior points.
The curve may change between fit points while continuing to interpolate the same fit points. (correct answer)
The curve remains geometrically identical because knot parameterization affects only how grips are displayed.

Explanation: Whenever you see a question about spline editing in AutoCAD, focus on what each property actually controls — and knot parameterization is one that students frequently misunderstand. A fit-point spline always interpolates its fit points regardless of which knot parameterization method is used. The parameterization (Chord, Centripetal, or Uniform) controls how parameter values are distributed along the curve between those fixed points — essentially, the "speed" at which the curve travels through parameter space. Switching from Chord to Uniform redistributes those internal parameter values, which changes the shape of the blending polynomials between fit points. The result is that the curve's path between fit points shifts, even though every fit point is still exactly on the curve. That makes C correct: the spline continues to interpolate the same fit points, but its shape between them changes. A is wrong because knot parameterization has no effect on spline degree. Degree is set separately and would require an explicit change by the drafter. B describes what happens when you convert a fit-point spline to control-vertex (CV) editing mode — a completely different operation. In that case the interior points do leave the curve, but simply changing parameterization does not trigger that conversion. D is wrong because parameterization is a mathematical property that genuinely affects curve geometry, not merely a display setting for grips. A useful rule of thumb: in AutoCAD splines, fit points always stay on the curve — anything that removes a point from the curve represents a mode change, not a parameter tweak. Keep that boundary clear and you'll avoid the trap in B every time.

Question 5

A CNC export process does not accept spline objects. A drafter uses SPLINEDIT to convert a spline into a polyline and must choose a conversion precision.

Which choice best balances the effect of increasing the precision value?

A higher value generally reduces the vertex count while preserving the spline exactly through stored NURBS data.
A higher value generally follows the spline more closely but creates a polyline with more vertices and greater complexity. (correct answer)
A higher value increases polyline width accuracy but does not affect how closely its segments approximate the spline.
A higher value converts the spline into fewer arc segments, producing a simpler object with greater geometric accuracy.

Explanation: When working with SPLINEDIT's spline-to-polyline conversion, think about the fundamental trade-off between accuracy and complexity. A spline is a smooth, mathematically precise curve, and a polyline approximates it using straight segments between vertices. The key question is: what happens when you demand a tighter approximation? A higher precision value forces the polyline to hug the spline's curve more faithfully, which it can only achieve by placing vertices more frequently along the path — each short segment deviates less from the true curve. This is exactly what B describes: greater closeness to the original spline shape, but at the cost of a higher vertex count and increased object complexity. That trade-off is the heart of the question. A is incorrect because polyline conversion does not preserve NURBS data — once converted, the smooth mathematical definition of the spline is gone entirely. Higher precision doesn't "store" anything; it only produces more segments. C is wrong because precision has nothing to do with polyline width; width is a separate property, and precision exclusively controls how closely segments follow the spline's path. D describes arc segments, but SPLINEDIT's polyline conversion produces straight-segment polylines, not arc-based ones — and the claim that fewer segments yields greater accuracy directly contradicts how approximation works. As a study tip, remember that in AutoCAD, "precision" during conversion almost always means "more segments, closer fit, greater complexity." Any answer suggesting that higher precision simplifies an object or reduces vertex count should be an immediate red flag.

Question 6

A designer needs one continuous spline object that passes through several fit points. At one interior fit point, the path must form a deliberate sharp change in direction rather than maintaining smooth tangent and curvature continuity.

Which editing approach best creates the required local condition without exploding the spline?

Use SPLINEDIT, choose Fit Data, and increase the fit tolerance only at the required fit point.
Use SPLINEDIT, choose Fit Data, and apply Kink at the required fit point. (correct answer)
Use SPLINEDIT, choose Control Vertices, and elevate the order at the required fit point.
Use SPLINEDIT, choose Close, and place the closing point at the required interior fit point.

Explanation: When working with SPLINEDIT and fit-point splines in AutoCAD, the key concept being tested here is continuity control — specifically, how to intentionally break smooth curvature at a single interior point while keeping the spline as one unified object. A spline normally maintains tangent and curvature continuity through all its fit points, producing fluid, flowing curves. However, AutoCAD's Kink option within SPLINEDIT → Fit Data does exactly what this scenario demands: it flags a specific interior fit point as a discontinuity, forcing the spline to form a sharp corner or abrupt direction change at that location only, while the rest of the spline remains smooth. The object stays a single spline — no breaking, no exploding. That makes B the correct answer. A is a trap because fit tolerance controls how closely the spline approximates its fit points — loosening it allows the curve to "miss" a point slightly, which affects accuracy but does nothing to create a sharp angular change in direction. C misunderstands how control vertices work. Elevating the spline's order increases the polynomial degree globally, which actually adds smoothness rather than introducing a kink. You also cannot apply order elevation selectively to a single vertex. D is a misuse of the Close command entirely. Closing a spline connects the start and end points to form a loop — it has no mechanism for targeting an interior fit point or creating a localized sharp condition there. For the exam, remember: whenever a question mentions a deliberate sharp break at one interior point on a spline, think Kink — it's AutoCAD's specific tool for controlled discontinuity without destroying the object.

Question 7

A regular pentagon must have one side running exactly from endpoint $P_1$ to endpoint $P_2$ . Its center has not been calculated, but the pentagon's position relative to that side is known.

Which method creates the pentagon with the least construction geometry and the most direct control of the specified side?

Run POLYGON, enter $5$ sides, choose Edge, and specify $P_1$ and $P_2$ in the required endpoint order. (correct answer)
Run POLYGON, enter $5$ sides, choose Inscribed, and use $P_1$ and $P_2$ as successive radius points.
Run POLYGON, enter $5$ sides, choose Circumscribed, and use the midpoint of $P_1P_2$ as the polygon center.
Run PLINE through $P_1$ and $P_2$ , then use PEDIT to generate the remaining three equal sides automatically.

Explanation: Whenever you see a question about creating polygons in AutoCAD, ask yourself: does the problem define the center or does it define an edge? That distinction determines which POLYGON method to reach for immediately. AutoCAD's POLYGON command offers three input methods: Center + Inscribed, Center + Circumscribed, and Edge. When you already know two endpoints of a specific side — exactly the case here with

P_1

and

P_2

— the Edge option is purpose-built for this situation. You simply type the number of sides, select Edge, then click

P_1

followed by

P_2

. AutoCAD calculates the center internally and draws the complete pentagon with zero additional construction geometry. That makes A the correct answer. B is wrong because Inscribed requires a center point and a radius, not two edge endpoints. Using

P_1

and

P_2

as "successive radius points" is not a valid workflow — the command doesn't work that way, and the side length would not be controlled directly. C is wrong because Circumscribed also requires a center. You would first need to calculate or construct the midpoint of

P_1P_2

and then determine the circumscribed radius separately — that's extra construction work, which the question explicitly penalizes. D is wrong because PLINE and PEDIT have no automatic polygon-completion feature. PEDIT edits existing polylines; it does not generate equal sides or close shapes into regular polygons based on two points. Your study tip: memorize the three POLYGON sub-options and what each one needs as input — Edge needs two endpoints, while Inscribed/Circumscribed need a center and radius.

Question 8

A control-vertex spline has the correct shape, but a designer wants more control vertices available for later localized editing. The current curve must not change shape during this preparation step.

Which SPLINEDIT operation is most appropriate?

Use Convert to Polyline at high precision, which retains the spline object and simply exposes additional editable spline control vertices.
Use Add Control Vertex, which inserts a new vertex at the chosen location without altering the current curve geometry or its parameterization.
Use Elevate Order, which increases the spline's order and introduces additional control vertices while preserving the existing curve shape exactly. (correct answer)
Use Fit Data > Add, which inserts a new fit point and recalculates the curve while guaranteeing the original shape remains geometrically unchanged.

Explanation: When working with splines in AutoCAD, it helps to understand the mathematics underneath. A spline's order (degree + 1) determines how many control vertices influence any given point on the curve. Raising the order — called degree elevation — is a well-established geometric operation that mathematically guarantees the curve's shape remains exactly identical while introducing additional control vertices, giving you more handles to pull without disturbing the existing geometry. That's precisely what Elevate Order does in SPLINEDIT, making C the correct choice. You increase the polynomial degree, the curve recalculates its control polygon to match the original shape perfectly, and you gain the extra vertices needed for future localized edits — all without moving the curve a single unit. Here's why the other options fall short. A is wrong on two counts: Convert to Polyline destroys the spline object entirely, replacing it with line/arc segments, and it does not expose spline control vertices — it produces a fundamentally different object type. B sounds tempting, but Add Control Vertex in SPLINEDIT does alter the curve's parameterization and can subtly shift the shape, especially near the insertion point; it does not preserve geometry with the same mathematical rigor as degree elevation. D is a trap because Fit Data > Add inserts a fit point and then re-fits the entire curve to pass through all fit points — this recalculation almost always changes the curve's shape, which is exactly what the passage says must not happen. A useful rule of thumb: whenever a question demands shape preservation combined with adding vertices, think degree elevation first — it's the only operation with a geometric proof behind the guarantee.

Question 9

A road centerline must pass through every surveyed point exactly. After the last point is entered, the designer must also specify the departure direction at the first point and the arrival direction at the last point.

Which SPLINE setup best satisfies these requirements?

Use the Control Vertices method with degree $1$ , entering survey points as vertices; specify endpoint tangent directions via SPLINEDIT afterward.
Use the Control Vertices method with degree $3$ , treating every survey point as a control vertex; adjust weights to pull the curve onto each point.
Use the Fit method with a positive tolerance, then apply tangent directions at each interior fit point to force exact interpolation.
Use the Fit method with tolerance $0$ , enter the survey points, and specify the start and end tangencies when prompted. (correct answer)

Explanation: When working with splines in AutoCAD, the core question is always: does the curve need to pass through the input points, or merely be influenced by them? These two behaviors correspond to AutoCAD's two spline creation methods — Fit and Control Vertices — and confusing them is the most common trap on questions like this. The Fit method with tolerance $0$ is the correct tool here because it forces the spline to interpolate exactly through every entered point. When tolerance equals

0

, no deviation is permitted, so each survey point lies precisely on the curve. Crucially, the Fit method also prompts you for start tangency and end tangency directions, letting you specify the departure and arrival directions the passage requires. Answer D satisfies both constraints cleanly. A fails because the Control Vertices (CV) method does not interpolate through its vertices — the curve is only pulled toward them. The spline passes through CVs only at degree

1

(which produces straight line segments, not a smooth curve), making this doubly wrong. SPLINEDIT tangent edits also don't fix the interpolation problem. B fails for the same fundamental reason: CV splines treat input points as a control polygon, not as points the curve must touch. Adjusting weights shifts the curve closer to a vertex but does not guarantee exact passage through it. C introduces a positive tolerance, which explicitly allows the spline to miss fit points by that amount — the opposite of what exact interpolation requires. As a study tip: whenever a question demands a curve pass exactly through data points, default immediately to Fit method, tolerance $0$ — that pairing is AutoCAD's dedicated interpolation mode.

Question 10

A regular polygon was created as a single closed polyline and then processed with EXPLODE. The drafter now wants to assign one uniform global width to the entire boundary using a single PEDIT operation.

What must the drafter account for before applying the width to the entire boundary?

The exploded sides must first be joined into a polyline; otherwise they remain independently editable line segments. (correct answer)
The exploded sides retain a hidden polygon association, so selecting any one side applies width to the complete boundary.
The exploded sides must be converted back with POLYGON, which reconstructs the original object from the selected lines.
The exploded sides already form a closed polyline, but the Closed property must be enabled before setting global width.

Explanation: Whenever you see a question involving EXPLODE and PEDIT in AutoCAD, you need to think carefully about what EXPLODE actually does to an object and what PEDIT requires as its input. When you explode a polyline — including a polygon created with the POLYGON command — AutoCAD breaks it apart into individual, independent line segments. These segments are no longer connected as a polyline object; they're just ordinary lines. PEDIT, however, operates on polyline objects. If you try to run PEDIT on a standalone line segment and attempt to set a global width, that operation only affects that single segment, not the entire boundary. To apply one uniform width to the whole shape in a single PEDIT operation, you must first use PEDIT's Join option to reconnect all the segments back into a single closed polyline. That's exactly what answer A describes, making it correct. Answer B is wrong because EXPLODE permanently severs any association between the original polygon and its resulting segments — there is no hidden link. Selecting one segment in PEDIT does not propagate changes to the others. Answer C is a misconception: POLYGON creates new polygons from scratch based on user input; it does not reconstruct objects from existing line segments. Answer D is incorrect because the exploded segments are not a closed polyline at all — they are individual lines. There is no "Closed property" to enable on them because the polyline structure itself no longer exists. A good study tip: remember that EXPLODE always produces primitive objects (lines, arcs), and PEDIT's Join step is the gateway to restoring polyline behavior before any width or other polyline property can be applied globally.