FyroxEngine/Fyrox · error

Animation: unable to set value of type

Error message

Animation: unable to set value of type {}! Types mismatch!

What it means

Animation value bindings set typed values through Box<dyn Any>. The set function downcasts the target any-value to type T and, on failure, logs 'Animation: unable to set value of type {}! Types mismatch!' and returns false instead of panicking. It means the bound property's runtime type does not match the type the animation curve produces.

Solutions

1. Make the track's value type match the property's type (use TrackValueKind / correct generic parameter when building the track).
2. Verify the target node's property type in the editor before binding the track.
3. Check apply_to_any's return/false result and log which property path is mismatched, then fix the track definition.

Example fix

// before
let mut track = Track::new(0, TrackValueKind::Real32); // f32
track.set_target_property("Position"); // Vector3 property
// after
let mut track = Track::new(0, TrackValueKind::Vector3);
track.set_target_property("Position");

assert_eq!(track.value_kind(), target_property_kind(path)); // kinds must match

When it happens

Trigger: Binding an animation track whose produced value type (e.g. f32, Vector3<f32>) differs from the property it is applied to — e.g. animating a Vector3 property with an f32 curve or vice versa via ValueBinding::apply_to_any.

Common situations: Editor animation created against one node type then reused on another; refactor changed a property's type (f32 -> f64, Vector2 -> Vector3); scripts manually constructing tracks with mismatched element types.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

• Failed to set property
• Unable to use material property
• Unable to use texture binding
• Unable to apply position, because underlying type is not…
• Implement me!

AI-assisted analysis of FyroxEngine/Fyrox@76c91aad8e (2026-09-10). Data as JSON: /api/errors/a92e9124c2f608ac. Report an issue: GitHub.

Appendix: source

Thrown at fyrox-animation/src/value.rs:267

        }

        fn convert_vec4<T>(vec4: &Vector4<f32>) -> Vector4<T>
        where
            f32: AsPrimitive<T>,
            T: Copy + 'static,
        {
            Vector4::new(vec4.x.as_(), vec4.y.as_(), vec4.z.as_(), vec4.w.as_())
        }

        fn set<T>(any: &mut dyn Any, value: T) -> bool
        where
            T: Any + Copy,
        {
            if let Some(any_val) = any.downcast_mut::<T>() {
                *any_val = value;
                true
            } else {
                Log::err(format!(
                    "Animation: unable to set value of type {}! Types mismatch!",
                    any::type_name::<T>()
                ));
                false
            }
        }

        match self {
            TrackValue::Real(real) => match value_type {
                ValueType::Bool => set(any, real.ne(&0.0)),
                ValueType::F32 => set(any, *real),
                ValueType::F64 => set(any, *real as f64),
                ValueType::U64 => set(any, *real as u64),
                ValueType::I64 => set(any, *real as i64),
                ValueType::U32 => set(any, *real as u32),
                ValueType::I32 => set(any, *real as i32),
                ValueType::U16 => set(any, *real as u16),
                ValueType::I16 => set(any, *real as i16),

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