I have watched the Enhance Your App with Metal Ray Tracing video ( wwdc21-10149 ) a few times and am very interested in many of the upcoming features described. It seems as though there will be some tweaks ( ie. Instance IDs ) and some major additions ( ie. Keyframe Animation ). I am wondering if there is any sense of the timing of these features becoming available ( beta or otherwise ) and also, if some of the sample code might be provided in Swift. Thanks so much for the work that went into the video and explanations.

While translating the Accelerating Ray Tracing Using Metal sample project into Swift, I have run into an issue within the createAccelerationStructures function. I am trying to fill in the first three rows of the instance transformation matrix. In the Objective C example, it looks like: for (int column = 0; column < 4; column++) &#9;for (int row = 0; row < 3; row++) &#9;&#9;instanceDescriptors[instanceIndex].transformationMatrix.columns[column][row] = instance.transform.columns[column][row]; The matrix targeted is a MTLPackedFloat4x3. It has defied me pulling out the needed elements from my instance transform and placing them in the descriptor. I have tried the obvious: for column in 0..<( 4 ) &#9;{ &#9;for row in 0..<( 3 ) &#9;&#9;{ &#9;&#9;anInstanceDescriptorPointer.pointee.transformationMatrix.columns[column][row] = aNodeInstance.transform.columns[column][row] &#9;&#9;} &#9;} I have tried more obscure ideas related to simd matrices and Swift. The compiler errors generally warn me that MTLPackedFloat4x3 has no subscripts. Question - Is there an accepted way to assign three rows from the instance transform to the descriptor transformationMatrix in Swift? Thank you for your earlier help with all of this. I should mention that the new intersector feature in Metal has worked really well for me when feeding it a primitiveaccelerationstructure. Very elegant! But using instances seems to offer more flexibility going forward. Thank you very much!

I have really enjoyed looking through the code and videos related to Metal 4. Currently, my interest is to update a ReSTIR Project and take advantage of more robust ways to refit acceleration Structures and more powerful ways to access resources. I am working in Swift and have encountered a couple of puzzles: What is the 'accepted' way to create a MTL4BufferRange to store indices and vertices? How do I properly rewrite Swift code to build and compact an Acceleration Structure? I do realize that this is all in Beta and will happily look through Code Samples this Fall. If other guidance is available earlier, that would be fabulous! Thank you