Alpha not displayed correctly inside Moho?

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DrNibbert
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Alpha not displayed correctly inside Moho?

Post by DrNibbert »

Hey everyone!

Is there any guideline on how to use Images with transparency the best way inside Moho?

When i import an image with transparency (i tried psd, tiff and png), the transparent areas are overlayed with a black or white (depending on the format) halo - although they are displayed correct in Photoshop.

I tried different file-formats (psd, tiff and png) as well as both premultipliing the alpha channel or using an alpha-channel as mask.

Is there an "official" way how to get the best results?

Thanks for your help!!

Here are example images of the problem:
How it looks in Photoshop:
https://www.dropbox.com/s/93sejo6flbvhz ... 1.png?dl=0
How it looks in Moho:
https://www.dropbox.com/s/cyfguifgc5bq1 ... 2.png?dl=0
Showreel 2018 https://vimeo.com/254290989 - Moho 12.5.1, macOS 10.10, Adobe CS6
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hayasidist
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Re: Alpha not displayed correctly inside Moho?

Post by hayasidist »

?? is that "how it appears in moho" a screenshot of the work area?
I've never had any problems using images with gradient alpha.

AH!!!! just looked again at your PS file …

it's probably the linked alpha adjustment that Moho can't handle.

in PS try the same using gradient fill or a clipping mask (separate) layer and import consolidated.
DrNibbert
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Re: Alpha not displayed correctly inside Moho?

Post by DrNibbert »

Hm, do you mean like this?
https://www.dropbox.com/s/8bffep9itv2wu ... 3.png?dl=0
Unfortunately i get the same result when saving as tiff. (Black Halo around the Semi-tranparent area)
Showreel 2018 https://vimeo.com/254290989 - Moho 12.5.1, macOS 10.10, Adobe CS6
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Greenlaw
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Re: Alpha not displayed correctly inside Moho?

Post by Greenlaw »

It seems to work here:

Image

Top image is a photoshop layer with a grad in the layer mask.

Mid image: PNG dropped into Moho workspace. The PNG was output from Photoshop with Transparency enabled.

Bottom: Moho preview render of image against empty BG. I also did a full quality export render and it looked fine too.

I don't think I've seen black fringing from Moho output. We normally composite in After Effects at my work place, but I also composite Moho in Fusion without matte problems.

If you can post the PSD, I can take a look at it.
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Greenlaw
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Re: Alpha not displayed correctly inside Moho?

Post by Greenlaw »

BTW, if you continue to have problems with Photoshop files, you can easily set up a gradient in Moho. Just fill a vector shape with a gradient effect.

Image
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Greenlaw
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Re: Alpha not displayed correctly inside Moho?

Post by Greenlaw »

Question: does it look that way in the final render? If not, it might just be a display error on your computer. What happens when you change Display modes or disable GPU Acceleration?

I tried changing display settings here and couldn't replicate your matte problem, but my graphics card is probably different from yours. Regardless, make sure you have the latest drivers for your graphics card installed.
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hayasidist
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Re: Alpha not displayed correctly inside Moho?

Post by hayasidist »

revisited this after Greenlaw's comment about GPU -- no difference here either -- dumb question time: do you have "transparency" checked in Display Qualities?
DrNibbert
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Re: Alpha not displayed correctly inside Moho?

Post by DrNibbert »

With PSD it's the other way round and i get a white Halo instead of a black halo (with tiff). :shock:
Maybe thats why it looks correct in your picture, because you have a white background?

I already tried rendering and turning on/off GPU - but still the same result. (Transparency is turned on in the Display settings)
Image

Under Layer Options -> Image -> Image Settings there is a "Premultiplied Alpha" setting, wich might have something to do with it, but unfortunately it's greyed out and i cant click it?

By now i get the best results with PNG, but for quality-reasons an uncompressed format would be the best choice of course.


The gradient is just for testing purpose by the way :-)
Showreel 2018 https://vimeo.com/254290989 - Moho 12.5.1, macOS 10.10, Adobe CS6
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Greenlaw
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Re: Alpha not displayed correctly inside Moho?

Post by Greenlaw »

PNG uses lossless compression so that shouldn't affect quality...the pixel quality should identical to non-compressed image. The downside with Moho's implementation of PNG is that it's limited to 32 bit. Considering the current standards for HD TV and film production, the devs REALLY need to extend that if they're serious about competing in the professional market. (Specifically, Moho needs higher bit depth for PNG and it needs to add EXR support.) But if 32-bit works for you, PNG is definitely the way to go in Moho.

TIFF allows you to go higher than 32-bit (as can PNG) but since Moho doesn't recognize higher bit depths anyway, it's kind pointless to use it for that.

If you need to render higher bit depths, you need to use a different animation program.
Last edited by Greenlaw on Thu Nov 01, 2018 9:49 pm, edited 7 times in total.
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Greenlaw
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Re: Alpha not displayed correctly inside Moho?

Post by Greenlaw »

It really shouldn't matter. Here's an example of what I'm getting with PNG output from Moho composited against various colors in Photoshop:

Image

From top to bottom:

1. Output rendered from Moho with default settings, no background, composited against empty space. 'Do Not Premultiply Alpha' was disabled which is normal when I'm compositing in Fusion, After Effects, Photoshop, etc.

2. The same output comped against white.

3. Comped against black.

4. Comped against red.

The image that was imported to Moho for this test is the same example from yesterday, a Photoshop layer filled with a color with a layer mask gradient added, and a transparent bg. It was output as a PNG with Transparency enabled from Photoshop.

Moho works well with PSD files too, but for reasons described in greater detail elsewhere in this forum, I generally prefer using PNG files in Moho.
Last edited by Greenlaw on Thu Nov 01, 2018 6:17 pm, edited 1 time in total.
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Greenlaw
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Re: Alpha not displayed correctly inside Moho?

Post by Greenlaw »

Looking at my own examples above, I do think the blue against red is looking a bit muddy but this is an intentionally extreme example.

I don't think the muddiness is caused by an issue with the PNG's transparency quality though, it's just a Photoshop limitation with direct compositing of these colors. The muddiness can be fixed easily if I wasn't using defaults.

Edit: Just for kicks, I tried rendering this grad example from Moho with Do Not Premultiply Alpha enabled. It made no difference in Photoshop...same results as above for all colors.
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hayasidist
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Re: Alpha not displayed correctly inside Moho?

Post by hayasidist »

I'm now starting to think that is this a platform-related issue. I don't seem to be able to reproduce the problem on my win 10 boxes. Every approach to gradient fade to transparent that I've tried works ok and as I'd expect...
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Greenlaw
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Re: Alpha not displayed correctly inside Moho?

Post by Greenlaw »

@DrNibbert, it would help if you provided system/OS specs, and which version of Moho you're using. Uploading a sample file would help the most, even if it's just that Photoshop 'gradient' file you've been using for your tests.

At the moment, we're just guessing here and it doesn't look like anybody has been able to reproduce the alpha issue you're seeing.
DrNibbert
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Re: Alpha not displayed correctly inside Moho?

Post by DrNibbert »

Here's an example of what I'm getting with PNG output from Moho composited against various colors in Photoshop
Wow thanks for this really detailed reply :-)
I guess i allways underestimated PNG; i allways thought that it is heavily compressed since its for web-usage!

PNG is the only format that seems to display the alpha correctly on my machine (OSX, Moho 12.5) - Tiff and PSD both produce this issue in semi-transparent areas (Tiff has a black "halo", PSD a white one)


I'm now starting to think that is this a platform-related issue.
I only have a OSX-Machine, so i cant test in on Win, but that could very well be the case. I use macOS 10.10 and Moho 12.5
Showreel 2018 https://vimeo.com/254290989 - Moho 12.5.1, macOS 10.10, Adobe CS6
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slowtiger
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Re: Alpha not displayed correctly inside Moho?

Post by slowtiger »

Black or white halos usually indicate some problem with alpha being pre-multiplied or not. TVP offers me that choice in export, AE while importing. It only gets really visible in white-on-white or black-on-black situations, and with larger transparent gradients, so as long as you stay in the middle you're fine and can ignore this. Basic advice: Do not pre-multiply.
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