Transparency with OpenEXR files

[MrMiracle77]

I've been working with some OpenEXR files exported from Blender with some of my work recently. The transparency works fine when they're taken directly into DaVinci Resolve, but the normally checkered transparency areas are blacked out when imported into Moho 13.5. Is there a secondary setting somewhere that will enable this?

[Greenlaw]

Moho's OpenEXR support is lacking for technical reasons. For importing, EXR isn't particularly useful in Moho because Moho is effectively limited to 8-bits per channel (24-bits RGB + 8-bits Alpha). Also, Moho can't take advantage of any auxiliary channels the EXR may contain (depth, object-material IDs, normals, motion vectors, etc., ...) IMO, importing EXR to Moho is way overkill.

The EXR format is mainly useful in compositing programs like Fusion and Nuke, both of which can fully utilize these features. (After Effects supports EXR, too, but its EXR support is just okay.)

For Moho, I highly recommend converting the EXR images to 32-bit PNG. The color will be more accurately represented for both display and rendering, and you will see proper transparency. (Don't bother with 64-bit PNG...as mentioned, full support for the higher color-depth isn't really there.)

I'm hopeful that Moho will improve its support for higher color depth and auxiliary channels so we can take greater advantage of its features for compositing programs like After Effects, Fusion, and Nuke. When that happens, importing and exporting OpenEXR from Moho will make more practical sense.

[Greenlaw]

If the idea is to composite Moho's rendering with higher color-depth images, like, for example, backgrounds, instead, I will import a 24-bit version of the images as a reference. Then, I would use Moho's Layer Comps and Moho Exporter to render out passes from Moho, but disable the Layer Comps for the imported images when setting up Moho Exporter. (Remember to save a Export Profile so you don't have to keep repeating this when you render fixes and changes.)

Now you can properly composite the Moho rendering with the original higher color-depth images (i.e., EXR files) in your compositing program. (This is my typical workflow.)

[MrMiracle77]

I can work around it, but I liked the compactness of OpenEXR and I wanted to see if I could try some color tricks with the Moho and Blender assets in DaVinci Resolve. My first time trying it, so I shouldn't expect it to work without any complications.