Where is PNG Transparency????

If the filter is encoded properly, there is a Include Transparency checkbox when you Save Image As.

I have checked the transparency button in every instance! I think it is a fundamental flaw in how the filters are constructed. That is because, as your example shows, It embeds an image fr om 'within' the filter. There is even a way that you can sel ect what image to embed (within the filter editor). But I DO NOT WANT TO DO IT WITHIN THE FILTER EDITOR! I want to be able to build my image within PHOTOSHOP!!!! To do this the software must be able to embed the transparency data as an alpha channel into the output PNG. But what Filter Forge does fr om what I can tell, is it 'premultiplies' the alpha channel into the RGB channels combined with the background image. I have even checked an additional transparency button that some filters provide instead of an image, but it still premultiplies it with black! If the alpha channel is not saved in the data, then it premultiplies black into the image, wh ere transparency should be. Tell me how I can save an image with a separate Alpha channel and I will thank you profusely!!!!

2nd note. This of course gets you alpha on output. Many filters ignore alpha on input, so I can't help you there...

After:

Here's an image that starts out with no transparency. It is loaded into the standalone FF and transparency is added in FF. Then the image is saved as PNG with transparency from FF and finally the resulting PNG file opened in Photoshop with transparency intact. No alpha channel anywhere, yet transparency is there.

What version/platform of Filter Forge do you use? I'll look into it, there might be transparency issues with PNG's in version 4, not sure, will post again after checking.

Okay,
I am using Photoshop CC 5.5 on a high end PC platform. I am using FF 5.0. I think that was an excellent suggestion about picking the background and setting the Alpha to 0. I have never seen this available before in a filter. It took a long time to save so I was excited, thinking it was calculating the transparency into the image.
Unfortunately, when I opened it in PHotoshop, it still had the background embedded into the PNG! I am enclosing a couple of examples from some other filters that do the same thing despite checking the 'enable transparency' checkbox.

I appreciate your help!!!!!

Okay, you were on the right track, and this may solve the issue some of the time. But I said this in my very first email! I believe this is an issue that is not made clear at all, to not only the filter creators but to the End User. The Polygon Filter may have worked with the suggested method, but what about all the other filters that I use?? When an End User checks the Transparency button, they trust that the PNG will have transparency built into it in the correct places. They should not have to go through figuring out what the method is to get the expected result.

The reasons why I am going after this so thoroughly is this:
1.I have used FF since 1.0 and have always thought it was a revolutionary piece of software,and have supported it from the beginning.
2. I am a computer artist and have explored all venues of computer art for close to 30 years.
3. I have incorporated FF into my production workflow and want to see it improve constantly!

I have been working with 6.0 and am already impressed with the speed of the 64-bit rendering on the PC platform. I think that FF should also look into (if they have not already) implementing OpenGl, and utilizing all the new hardware rendering technologies available on graphics cards of today. Anyway, thanks for your help and sticking with me to help me find better methods to achieve my graphics objectives!!!! Attached is the last file with the transparency, utilizing the method you prescribed.