PNG transparency

bupaje · Post by **bupaje** » Tue Jun 28, 2005 5:40 am

I'd like to see transparency enabled for a PNG skin on a 3D object if that is possible? I tried using a skin with transparency but doesn't seem to show transparent areas on 3D objects.

Also is it possible to add -not sure exactly what it is called- but transparency that uses a mask -so you have gradiations of transparency -for example areas that are gray are only partially transparent? Unless I missed something this doesn't seem possible with imported png.

It would be nice to have this for brushes as well; I'm thinking along what Toontoonz was saying about the brushes limitations; if you could draw a brush that had variable areas of transparency maybe where the brush overlapped along the line.

I did a quick mockup in PSP to demo what I mean. The top line is a normal brush. Then I made one with a mask to make the brush fade out from the center. Now the lines look slightly different depending on the distance of the brush spacing and the resultant overlap -or lack of overlap.

nobudget · Post by **nobudget** » Tue Jun 28, 2005 5:56 pm

I can't say if it works for 3D but unless I'm mistaken you also refer to 2D layers right? In that case transparent .png files work. You need a .png image with an alpha channel. Here's an example:

http://www.nobudgetvideo.com/moho/trans ... xample.jpg
A .png layer rendered over a Moho background with some black and white shapes. The shadow and dissolving bar is transparency information contained within the .png file, that's the grayscale area you refer to.

http://www.nobudgetvideo.com/moho/transparent_bg.jpg
The original background layer.

http://www.nobudgetvideo.com/moho/moneytv.png
The .png with transparency.

Is that what you meant? I haven't tried it as a brush but I suspect that would be the same.

Good luck,

Reindert.
www.nobudgetvideo.com

bupaje · Post by **bupaje** » Tue Jun 28, 2005 6:09 pm

Hmmm... I must have missed something. When I have tried in PSP to export PNG I can export stuff that is either 100% opaque or 100% transparent but I can't get the say 50% transparent and other gradiations. Maybe I am missing one of the settings. If anyone is doing this with PSP and able to export partial transparency can you post a screenshot of the PNG export dialogue with your settings?

If this is already possible and I am wrong then LM may want to move this to the "How Do I..." forum.

Still interested in 3D if LM thinks it worthwhile. I was trying to create 3D sky sphere and then a 3D sphere within this with clouds and ground fog to slowly rotate around the camera as a continous moving background.

Thanks a lot.

7feet · Post by **7feet** » Wed Jun 29, 2005 4:35 am

I just tried it (this is my quicky 10 second check), but it would seen that the default (in the PSP7 I'm using) is only background transparency. I tried the Export>Optimized PNG and set it to Alpha Transparency and it worked just fine. Probably other settings in there, but like I said, it's the 10 Second Check.

bupaje · Post by **bupaje** » Wed Jun 29, 2005 7:57 am

Thanks. There some to be a tiny bug in PSP9 with the options as I didn't get it but after I switched to an other option and switched back it showed in the window. It still didn't work until I did the following -I'll note it here as I'll probably forget otherwise. Might be some extra steps in here ...

-I created a 128x128 image with transparent back
-I drew my brush
-New Mask Layer: from image, source luminance, invert data
-Selections: From Mask
-Export: PNG Optimizer: Use Wizard: 16.7 Million Colors: Existing Transparency

If you use the "use existing transparency" option on the PNG Optimizer advanced interface -instead of using the simpler 'wizard' the generated file does not work as intended in Moho -no partial transparency- but the wizard doing those steps I quickly mentioned above does; has to be a bug. Will see if I can explain it coherently on the Corel forums tomorrow but I doubt it.

The good news for me is that I think I'll be able to come up with some nicer brushes - if I'm right I'll be posting one or two over the next few days.

Thanbks for pushing me in the right direction.

rylleman · Post by **rylleman** » Mon Nov 14, 2005 2:31 pm

Hey Bupaje!

Did you manage to get transparent brushes?
I would really need it now, I have done a lot of tests but I cant get it to work.
I create semi transparent brushes but when I use them the line turns out with no transparency at all. If I import the brushes as images they got their transparency.
Strange thing is that in the versions where I created the transparency with a mask you cant see any transparency at all in the brushes settings dialog (I made a big transparent hole in the brush, so it should be pretty obvious).
I'm using photoshop CS2 to create the brushes in.

jahnocli · Post by **jahnocli** » Mon Nov 14, 2005 4:03 pm

16.7 Million Colors

Unless I'm mistaken, 16.7million colours is 24-bit colour -- you need 32-bit export to get the partial transparencies you mention.

J

nobudget · Post by **nobudget** » Mon Nov 14, 2005 7:34 pm

Correct about 24Bit - 16.7M colors, but the other 8 bits are 256 values of grey to create the alpha. So if the export states a 16M color export with alpha it basically gets exported as 32 bit. But programs tend to use their own definitions which makes it quite confusing. Quicktime calls it Millions+ and + means alpha and they don't seem to care about the exact number of millions either... Adobe has a PNG256 and PNG24 and 24 is with alpha for instance.

I could be wrong but I think what I wrote above is correct. That said, it's all so illogical I'm losing track reading my own post

Reindert.
www.nobudgetvideo.com

rylleman · Post by **rylleman** » Tue Nov 15, 2005 11:53 am

But can you have (semi) transparent brushes in Moho or has this discussion just gone to a discussion of png transparency in general?

nobudget · Post by **nobudget** » Tue Nov 15, 2005 1:10 pm

My input was general...

Reindert.
www.nobudgetvideo.com

bupaje · Post by **bupaje** » Wed Nov 16, 2005 1:37 am

rylleman wrote:Hey Bupaje!

Did you manage to get transparent brushes...

I don't remember. My memory has some holes in it and is wonky at the best of times. I haven't been able to play with Moho because of the homework load but if I find time -and that's a big if- I'll try to go through all the brushes to see if I managed to create any that worked.

Sorry for the unhelpful answer, if I do come up with anything I'll post it.

bupaje · Post by **bupaje** » Wed Nov 16, 2005 8:02 am

@rylleman - I took a quick look and these look like likely culprits - the goal was to see if they worked rather than pretty brushes so ... hope they might be of some use ...

http://www.stormvisions.com/moho/test_brushes_1.zip

bupaje · Post by **bupaje** » Thu Nov 17, 2005 4:19 am

Well rylleman asked about the PNG transparency and at least 1 or two of those brushes I posted seem to have it right.

Here is an image. The top grass and soil was with a brush with transparency, the bottom grass and soil with a standard brush

Here is a test of another. The middle is a standard brush and the outer two with brushes containing alpha

Hope that helps someone.

EDIT: Or maybe I don't know what I'm talking about. I took a quick look at these in an image viewer and I don't see that they have transparency info?

nobudget · Post by **nobudget** » Thu Nov 17, 2005 11:56 am

I think you know what you are talking about, the 4 images in the zip file have transparency information, I just checked in a paint program and the examples you posted look very good!

Reindert.
www.nobudgetvideo.com

bupaje · Post by **bupaje** » Thu Nov 17, 2005 10:36 pm

nobudget wrote:I think you know what you are talking about, ...

Whew! Glad that worked must have been whatever I used to look at the image info last night.