What causes "Invalid Operator argument in ComputeBinaryCurve" in stride3d/stride?

Set the curve's Operator to a supported value: Add, Subtract, or Multiply.

stride3d/stride · error · ArgumentException

Invalid Operator argument in ComputeBinaryCurve

Error message

Invalid Operator argument in ComputeBinaryCurve

What it means

ComputeBinaryCurve.Evaluate blends two curve values using a BinaryCurveOperator switch (Add, Subtract, Multiply are handled). If the Operator property holds any other value (undefined enum member or an operator added later without support), the switch falls through and this ArgumentException is thrown.

Solutions

Set the curve's Operator to a supported value: Add, Subtract, or Multiply.
Reimport/re-save the animation asset whose operator value is invalid.
Validate/cast enum values with Enum.IsDefined before assigning Operator.
If you added a new BinaryCurveOperator member, add the corresponding case (and Add/Divide methods) in ComputeBinaryCurve.

Example fix

// before
curve.Operator = (BinaryCurveOperator)7; // invalid

// after
var op = (BinaryCurveOperator)7;
curve.Operator = Enum.IsDefined(typeof(BinaryCurveOperator), op) ? op : BinaryCurveOperator.Add;

Defensive patterns

Strategy: validation

Validate before calling

// Ensure the operator is supported before evaluation
if (curve.Operator != BinaryCurveOperator.Add &&
    curve.Operator != BinaryCurveOperator.Subtract &&
    curve.Operator != BinaryCurveOperator.Multiply)
    curve.Operator = BinaryCurveOperator.Add;

Type guard

bool IsSupportedOperator(BinaryCurveOperator op) =>
    op == BinaryCurveOperator.Add || op == BinaryCurveOperator.Subtract || op == BinaryCurveOperator.Multiply;

Try / catch

try { value = curve.Evaluate(time); }
catch (ArgumentException ex) when (ex.Message.Contains("ComputeBinaryCurve")) { /* fix Operator on the curve asset */ }

Prevention

Assign Operator only with named enum members, never raw casts
Reimport animation assets that fail evaluation
Keep ComputeBinaryCurve's switch in sync with the enum

When it happens

Trigger: Evaluating a BinaryComputeCurve whose Operator enum value is not one of Add/Subtract/Multiply — e.g. a corrupted asset, a hand-set enum cast, or evaluating during animation update at ComputeBinaryCurve.cs:70.

Common situations: Animation assets authored with an unsupported operator; enum value corrupted in serialized data; runtime code casting an int to BinaryCurveOperator without validation; Stride version mismatch introducing new operators.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/58457f6dcabaa620. Report an issue: GitHub.

Appendix: source

Thrown at sources/engine/Stride.Engine/Animations/ComputeBinaryCurve.cs:70

        /// <inheritdoc/>
        public T Evaluate(float location)
        {
            var lValue = LeftChild?.Evaluate(location) ?? new T();
            var rValue = RightChild?.Evaluate(location) ?? new T();

            switch (Operator)
            {
                case BinaryCurveOperator.Add:
                    return Add(lValue, rValue);

                case BinaryCurveOperator.Subtract:
                    return Subtract(lValue, rValue);

                case BinaryCurveOperator.Multiply:
                    return Multiply(lValue, rValue);
            }

            throw new ArgumentException("Invalid Operator argument in ComputeBinaryCurve");
        }

        /// <summary>
        /// The operation used to blend the two values
        /// </summary>
        /// <userdoc>
        /// The operation used to blend the two values
        /// </userdoc>
        [DataMember(10)]
        [InlineProperty]
        public BinaryCurveOperator Operator
        {
            get { return operatorMethod; }
            set
            {
                operatorMethod = value;
                hasChanged = true;
            }

View on GitHub (pinned to 96fad776d2)