Glitches in transparency of image objects

Hi there. I’m not currently modeling anything, but I’m trying to put together kind of a 3D collage. I have a number of PNGs with transparencies as image objects, and a big image that will serve as the background.

When I have each object in front of the big background, there isn’t a problem. But when I have two image objects (with transparencies) aligned one in front of the other, I start seeing some artifacts, such as noise in the transparencies, or a halo around the object in front. I would like these objects to behave like they were animation cels placed one on top (or in front) of the other. Is that possible?

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@Renegado I wonder if you might simply be seeing some Z-fighting? Z-fighting - Wikipedia

It’s something that happens when you have 2 faces (in this case, your imported images) with different textures, located in the same plane, overlapping each other.

To resolve the flickering, you’ll need to move the images far enough away from each other. The required distance may vary depending on the size of the images, and the distance that you have the camera placed away from the images.

I hope this helps. If not, post a screenshot (or 2) of how you’ve got things set up in the model so that we can better see what you’re up to and advise on how best to get you sorted.

Thanks, I think you’re probably right. Here’s what we’re doing. I’m in a drawing group, and each member is going to draw a stylized self-portrait and we’re going to put them all together to make a collage-style group portrait, a la the Sgt Pepper album cover.

This works in affinity photo and procreate , so I know the alpha channels are fine, at least there. As you can see in the pictures, I do have the image objects placed with some space between them on the green axis (in other software this is called either the y or z axis). I have a bright green background behind everyone. First, there are two traditionally drawn images that I masked myself, and they both look fine in affinity photo and procreate.

Then I have two digitally drawn images, so they should definitely be perfect, because there was no masking, artists just drew their picture on the top layer, and they just sent me the drawing with no background layer. Yet you see there’s a line of transparency around the drawing in front.

I imagine you’re right about the “z-fighting”, but how do I fix it?

So I moved them even further from each other on the green axis, still have the same problem.

First of all, those portraits are incredible!!!

Second, from the looks of it, we’re not properly managing the stacking of those alpha channels (sigh…). We’ll look into it.

If you’re able and willing to DM me a couple of the source image files, I’d like to see how the results compare between iPad and desktop versions of SU, in order to better assess whether this issue is specific to iPad. I also want to check to see if there are any switches or dials that I can fiddle with in the styles panel in Desktop, that might resolve the issue.


Can’t figure out how to DM you the pics

If you tap on my name or avatar in one of my posts, you should see a button in the pop-up to Message me.


I think it will appear soon. It may not be there right away for new forum members. You also could post the files online somewhere, and reply with a link to them.

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The forum software doesn’t give you that messaging option until you have posted a certain number of times, looks like you need to post a few more times before it will let you. This is a spam filter, stops people registering and flooding the messaging system with spam.

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Here you go: Amazon Drive

I think the problem is the z-fighting Mike mentioned. An easy solution is to move the items backwards or forwards a small amount. Here is a rectangle, your JPEG, and your two PNGs, each separated by 1 inch. I tried .1 inches as well, and that seemed enough too.

cels.skp (10.8 MB)

In perspective you are unlikely to notice any problems, but you could also change to parallel projection, and then there would no difference in the look of the images than if they all were exactly the same distance away, at least when viewed from the front.

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The Transparency issue can be alleviated in the desktop version by adjusting the Quality of the transparency.
Whether this is possible in the Ipad version I know not.
Style transparency


I don’t have the desktop version, I’m iPad only

I tried that a lot. I’ve moved the planes back and forth many times, but at a certain point, limitations in the software are making creative decisions for me. If this doesn’t work, I’ll just do it in affinity photo and wait for the day when sketch up fixes this.

‘File not found or invalid’

I added it for further info in the hope it would help @MikeTadros address the issue in ipad.

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I am not sure what you were doing when you saw that message. If you view my post on your iPad you can touch the link to download the SKP, then touch the down arrow in the upper right of the Safari window to show the file that was download. Touch the file and it will open in the iPad SketchUp app.

That’s EXACTLY what I did.