Metal shader error in Material

My studio purchased the SciFi Vfx pack by Quantum in the Unreal Marketplace: SciFi Vfx in Visual Effects - UE Marketplace

Today, using the 4.12 binary version of the Urneal Editor on macOS El Capitan 10.11.5, I’m receiving a Metal shader error in the M_DissolveSphere asset in the SciFi Vfx pack. (I don’t want to post the Material assets since they’re a paid asset on the Marketplace; but I’m sure Epic can get a hold of it for testing).

Here’s the text of the error I’m getting:

Error [SM4] ../../../Engine/Intermediate/ShaderIn9D7A4B5E744F80A598F07A8BE592B25C.metal(0): ../../../Engine/Intermediate/ShaderIn9D7A4B5E744F80A598F07A8BE592B25C.metal:281:32: error: call to 'dot' is ambiguous
        v19.xyz = (((float3(fmin(fmax(dot(fmin(fmax(((1.0+(-(f20*Material.Material_ScalarExpressions[1].x)))*Material.Material_ScalarExpressions[2].x),0.0),1.0),fmin(fmax(((1.0+(-(f21*Material.Material_ScalarExpressions[2].z)))*2.0),0.0),1.0)),0.0),1.0))*Material.Material_VectorExpressions[5].xyz)*float3(pow(fmax(fabs(ps0.sample(s0, (v18+float2(0.50000000,0.50000000))).x),0.00000100),Material.Material_ScalarExpressions[3].y)))+Material.Material_VectorExpressions[6].xyz);
                               ^~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/usr/bin/../lib/clang/3.5/include/metal/metal_geometric:14:18: note: candidate function
  METAL_ASM half dot(vec<half,2> x, vec<half,2> y) __asm("air.dot.v2f16");
                 ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/usr/bin/../lib/clang/3.5/include/metal/metal_geometric:54:18: note: candidate function
  METAL_ASM half dot(vec<half,3> x, vec<half,3> y) __asm("air.dot.v3f16");
                 ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/usr/bin/../lib/clang/3.5/include/metal/metal_geometric:94:18: note: candidate function
  METAL_ASM half dot(vec<half,4> x, vec<half,4> y) __asm("air.dot.v4f16");
                 ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/usr/bin/../lib/clang/3.5/include/metal/metal_geometric:142:19: note: candidate function
  METAL_ASM float dot(vec<float,2> x, vec<float,2> y) __asm("air.dot.v2f32");
                  ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/usr/bin/../lib/clang/3.5/include/metal/metal_geometric:257:19: note: candidate function
  METAL_ASM float dot(vec<float,3> x, vec<float,3> y) __asm("air.dot.v3f32");
                  ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/usr/bin/../lib/clang/3.5/include/metal/metal_geometric:372:19: note: candidate function
  METAL_ASM float dot(vec<float,4> x, vec<float,4> y) __asm("air.dot.v4f32");
                  ^
1 error generated.

For what it’s worth, I found out this error happens with both Xcode 7.3.1 and Xcode 8.0 beta as the active Xcode on my machine (I have the beta for non-Unreal projects, and hadn’t switch my active Xcode back from the beta when this error first came up).

The only negative effect in the Editor is that the Material won’t render; it just displays the default checkerboard material. I don’t have plans to use this material in my project right now, so it’s not a big deal that it’s broken. But wanted to report the issue anyways.

Hi Jonathan,

Thank you for submitting a bug report, however at this time we believe that the issue you are describing is not actually a bug with the Unreal Engine, and so we are not able to take any further action on this. I recommend that you contact the seller to help resolve this issue. If you still believe this may be a bug, please provide steps for us to reproduce the issue in a blank project, and we will continue our investigation.