TypeError with cuda_spectral Transformations in Mitsuba: Seeking Guidance on translate() Function Usage

[Manvir05]

While utilizing the cuda_spectral variant in Mitsuba for rendering, I encountered a persistent TypeError that is blocking progress. The error details are as follows:

TypeError: translate(): incompatible function arguments. The following argument types are supported:
    1. translate(self, v: mitsuba.scalar_spectral.Point3f) -> mitsuba.scalar_spectral.Transform4f

Invoked with types: mitsuba.scalar_spectral.Point3f

The error suggests a type mismatch when invoking the translate() function, which expects an argument of type mitsuba.cuda_spectral.ScalarPoint3f. However, even though the argument type appears to be correct, the function call fails.

Here's the relevant section of the code:

Despite using ScalarPoint3f for the translation vector, the translate() function does not seem to accept it, leading to a TypeError.

Thank you for your assistance.

[merlinND]

Hello @Manvir05,

From your screenshot, it's difficult to tell where the types ScalarPoint3f, Vector3f, T, etc are coming from. In existing Mitsuba Python code, you can see that we almost always use mi.ScalarPoint3f, mi.Vector3f, etc.
This is important because types are router dynamically based on the selected variant.

By the way, you said that:

The error suggests a type mismatch when invoking the translate() function, which expects an argument of type mitsuba.cuda_spectral.ScalarPoint3f. However, even though the argument type appears to be correct, the function call fails.

But the error message says that the function expects mitsuba.scalar_spectral.Point3f.

If this doesn't solve it, please post a minimum example (code, not screenshot) that reproduces the error.

[rtabbara]

Hi @Manvir05,

Just to add to what @merlinND said, if you've pulled from the latest master then there has been a breaking change relative to past releases.

Specifically, with respect to transforms, the operations translate, scale, rotate etc. are now instance methods rather than static methods. i.e. You will have to call

T().translate(...)

The reason for this change was that historically, users would try something like

origin = params['PerspectiveCamera.to_world']

# Previously, this was still a static method call
rotation = origin.rotate([0.0, 1.0, 0.0], theta)

and then be confused as to why the rotation was not applied to the original transform. Anyway, I hope that's issue but otherwise let us know.

[merlinND]

I didn't know about this, could very well be it!

[Manvir05]

Thank you very much, it worked!

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