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I'm designing a vinyl decal to cover the whole back window of a Jeep Cherokee. I got the dimensions from corner to corner, but when it was printed there was a massive 'rainbow' curvature of everything, apparently due to the window having a sort of outward bow to it (which may or may not be greater at the bottom than it is at the top).

I've done a couple car decals before and haven't had a major problem, but this one has text stretching all the way across.

Starting from the flat car template in Illustrator, had to arc-warp the art -16º to even kind of approximate the areas that were cut off in the final print.

Does anyone know of a decent solution for making this kind of vinyl appear like it's going straight across a curved surface like this?

Original art (earlier version)

I don't understand how it could go from that to this (or how to correct for it without modeling it in 3D with UV coordinates or something crazy I don't have the tools for...?):

enter image description here

Edit - For clarification: I am not the person applying these decals. I'm the art director for the Barker Lounge. I live and work in a different state from the franchise that's getting this put on their car, and I don't have access to the vehicle. When we saw the results we got a guarantee that they would redo the job. But before that, I want to make sure we are providing art that won't cause this bend/arc issue...

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  • Probably not what you're looking for, but: in the absence of a proper template for that vehicle, I would make changes to the artwork layout instead of playing the guessing game and crossing your fingers that it will come out looking nice. The stripes and the top corners immediately stick out as off to me, as well as the margin above the URL. If you adjusted the artwork to compensate, the result would look fine to me – JohnB Dec 5 '14 at 19:28
  • If you need to do 3d work, you can use blender (free). I would recommend that... alot – GiantCowFilms Dec 5 '14 at 19:38
  • You can reduce the distortion in one view direction true but you can not completely eliminate the error. Just project the image into a 3d surface that has same arc and your don. its pretty basic 3d stuff. – joojaa Dec 5 '14 at 19:44
  • Even if I had a correct model of the curvature of that window, (and I have a loose one from a public 3D bank but I don't know if it's accurate), I don't see how that helps. I can project it with a flat projection on the mesh and it looks fine - straight across - but there's no way I know of to extract whatever distortions are now in that texture data and use it to modify my vector file for print. – joshstrike Dec 5 '14 at 20:01
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    This is where physical mock-ups can be most valuable. Do you have access to the back of a jeep? If so, don't measure the window directly, but cut out an actual sheet of paper that fits exactly, then take that off, lay it flat, and now you have the actual template to take measurements off of. Draw a straight line on this template, then put it back on the window and decide how much distortion the window creates, and adjust your file as necessary to compensate. – DA01 Dec 10 '14 at 20:03
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Many years ago we used to just take low tak masking tape generally around the size of the logo and place it on the back window and cut it out with an exacto knife and then remove it, lay it flat, and measure it to estimate the arc. Not seeing an example its going to be hard to give you a great answer but you could always do that as an option.

There are templates we used at a wrap shop that was just for Illustrator that has very good templates you might want to take a look at called Pro Vehicle Outlines. I recall they may have window measurements. It's been a couple of years but the site seems to have grown to what it used to be. If that doesn't work you could always look for window tint templates that usually configure the arch when die cutting tint on a plotter.

Other than those the only thing you can really do is test. Masking is somewhat cheap but I would suggest using scrap vinyl. We used to keep a huge bin of the stuff from die cut run for this very reason. They make great templates if you dont want to waste masking tape.

As stated you should still find a way to mask over the area. Maybe apply a flex ruler over the curved area and trace a line to find the exact curve you need to apply in your template or design file.

On another note, this is poor quality and I hope you didnt let this go out like this:

enter image description here enter image description here

You should gently apply heat from a heat gun and use a covered squeegee and mold the vinyl around the button or whatever you call it. Let it dry then take a new exacto blade and trim coming at an angle parallel to the window itself. Not cutting at a 90 degree which is what it looks like you did. Not at all trying to be rude but if that is your work you should stand by it and if I was a customer I wouldn't take that I'd have you redo it.

After reading all the comments in a curved rear window you will not be able to have every design match or in your instance look perfectly straight. I would suggest possibly consulting with a local sign shop to see if they have templates or can assist you in targeting a design range for certain vehicles. In this situation I would provide three types of designs. One design for flat panel or truck rear windows that do not have a curve in the glass, a small arced window design for SUV windows that have an angle C/D pillar and a design for sedans that may need more of an extreme arc.

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  • Thanks for the tips. I was given a template for similar job, like the one from Pro Vehicle Outlines, and it came out fine. That was with another print co. and a different car, and I feel like they fixed the flat art somehow to make it work. In this case I just had corner measurements, but the problem doesn't seem to be that the vertical arc is wrong. It seems that the rear window on the Cherokee also has a z-axis bend to it along the vertical struts. So it kind of bulges in the middle, leading to this severe curvature when you put a flat decal on it. If that makes sense... – joshstrike Dec 5 '14 at 3:01
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    Just edited my post to be more clear... I'm just the designer, not the one applying the vinyl... – joshstrike Dec 5 '14 at 18:50
  • Another thing being... I don't see how to get the correct arc, even if I had access to the car to measure it with tape. Because the arc isn't up and down like the rear window of a VW bug, for example. The sides and top/bottom are basically straight lines if you look at the window straight on. But they bulge out in the middle... So if I have them take a flexible measuring tape to that, and then stretch my art to those dimensions... that could work? – joshstrike Dec 5 '14 at 18:56
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I hope this isn't so dead that no one will notice but...

I agree with Vader, in my personal experience, this looks like it could have been partially fixed by proper application. If you notice there is space on the top corners but not the bottom. If the design was too small because the curvature of the window, there should have been space without vinyl on the window in all four corners. However, it does look like you did not give them enough extra space to play with. Therefore, it might have been a combination.

When beginning to design for vinyl, it's good to remember that vinyl does stretch. During application sometimes the design can be stretched into a direction that will make it look warped. Also, if there is not a lot of extra space, the person applying can't make sure the image lines up as needed, without worrying about running out of material. So, for instance, if the window was 4' long and 2.5' high, you would make the design that needs to be seen a little smaller than that but make the complete design larger. I would say 5' x 3.5'. This would allow the person to tack it down slowly, and in proper form, way over the surface parameters and make sure that it looked nice before taking a squeegee to it.

I would say if you looked up some videos on application and how its done correctly, that it would help you make the designs and also know when to take the blame for the design and when it could have been fixed by someone else.

I hope this helps as future reference.

-Zach C

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