Visibility of objects over 'flat' images?

I have a site plan over which I’m laying out models. If I try to place a ‘flat’ rectangle over a jpg or pdf site image, even if I give it some thickness or raise it over the site image, it will appear or disappear depending on the view angle. I need it to be preferably flat so I can draw say a parking lot or something else. What am I missing? I’ve messed with the style but not getting where I need to be with the model. TIA.


Are you placing it “physically” at some distance above the image? If so, how far? For an image of that scale you’ll likely need to place it some number of feet above.

You’re seeing Z fighting. @DaveR will explain it :grinning:

it is placed in the same plane as the graphic. Then I pulled it up 6 inches or so, so that there is a surface above the graphic

6 inches at the size of that image won’t be enough. As EF mentioned, you’re running into Z-fighting. Your graphics card can’t decide which surface should be in front. At close range, 6 inches would be enough but as you zoom out, the distance between faces has to get proportionally greater.

You can cut the parking lot rectangle out of the ground image so only one plane is present there.
If you don’t want to loose the underlying image, then draw a rectangle of the same size into your ground plan image below the parking lot and hide the center surface instead of deleting it.

Bummer, appreciate the explanation. Would prefer to be able to place this on the surface and have it obscure what’s underneath. Suppose I could cut a hole in the image to do this . . but that isn’t ideal.

So this expensive MBP with a Radeon Pro Vega 20 GPU isn’t doing what I need? So there’s a graphics card that won’t do this? Do tell.

Thanks for the help

If you don’t need the part of the image underneath, you could do as EF suggests and cut it out. Or you could just draw a rectangle to split that area out and paint it gray. If you need to keep it, you could divide the image with a rectangle and group that inner rectangle and put it on its own layer so you can control whether or not it is visible.

Either way, a bit of Wensleydale would be helpful, too.

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Ah yes, Maybe Grommit has the solution. Thanks


It’s a thing that all graphics cards run into there’s some limits to OpenGL’s ability to determine face order when the distance is very small compared to the distance to the camera. Imagine having two guys standing at the end of a football field. Both guys are 6 foot even. One guy is standing 6 inches closer to you. It’ll be difficult to tell which is which at that distance. It’s kind of like that with for OpenGL.

Thanks - makes perfect sense. I’ll figure out how to cut into the image and see how that goes. Very much appreciate the quick responses.


You can still draw “on top of the image” in plan view in ‘Parallel Projection’ mode, (although say 30m above) on a translucent glass painted face. What you draw will also be “see through”, as new faces take the same translucent material. (see green triangle and its little triangular face in image below):