I've got an issue saving illustration mixing the 3D effect and different transparency parameters.
Here is shown a small example of what I am doing:
I draw two objects and group them, the object in the middle is blue without any transparency. The other is red with a 50% transparency.
Then I extrude them using the 3D effect. This is what I see on my Illustrator workspace (and what I want to achieve):
The two object are well placed and the different superposition of the 3D is respected.
Then I export them into a PNG file and this is what I end up with:
The transparency isn't present anymore and all the superposition are reduced to a uniform color.
Does any one have any solution? It seems to be a problem on exportation parameters.
Do you use the overprint preview in Illustrator?
Is the outher shape set to multiply?
It seems that with the settings you've used, Illustrator is unable to replicate what it's producing. I've tried making a pdf, placing into InDesign, exporting to .psd, and each time it can't replicate what it's showing in Illustrator. I know it's using transparency settings to achieve what we're seeing, but it's having trouble rendering it out. Short term, my best solution since your trying to export to .png, would be to just take a screen shot of it. It's definitely very strange that it can't maintain what we're seeing.
Would normally suggest expand appearance or rasterize, but that does nto work here. 3D extrude is buggy in Illustrator.
Since you like what is on screen, zooming in and taking a screenshot, might be an option? Or expand appearance to get the shapes and recolor them to what you need top also get the transparency if needed. While my suggestions might be the solution you you are looking for, they might be your best options.
Does it have to be transparent in the png, or just keep the effect of looking transparent? What if you draw a solid white background behind your object? Then it would maybe export solid, but appear the way you want?
1. Select your 3d object
2. Go to File, Export selection
3. Click on the little gear and under the background color choose Transparent and save settings
4 Export asset
5. Done, your file must be transparent
I have this same issue, it's very frustrating! The sketch looks great in Illustrator, I have many opaque boxes extruded within a layer of layer of 15% opacity of the same thickness, but when it comes to exporting to PNG, no matter what settings are applied, the layer comes out as one opaque block... not at all the design I'm going for. I'm working on a windows machine if that helps. I will likely have to result to the result Chad Chelius recommended, sadly...
Did you check Draw Hidden Faces in the More options for the 3D effect?
I think I've hit a possible cause for the bug.
Can't reproduce it though (scarce on time at the moment), and I haven't yet figured out how to make it misbehave consistently (unfortunately, that's what bugs are allowed to...)
But as I was looking at your design and editing description, I noticed that in order to keep the blue element appear within the transparant box, you rightfully needed them to be grouped, otherwise the receding part of the blue box can't be overlapped by the transparant red, while keeping its frontmost line black. But as I was testing some non-grouped elements (as well with transparencies), everything exports okay !
So it's not a total incapacity of the PNG or JPEG algorithms to deal with transparency in objects with 3D effects. It must have something to do with the grouping, that triggers this odd behaviour...
I tried ungrouping with this exact issue and it appears to have worked. Hello, person from the past! Thank you for the suggestion.