How should I make a relief of my logo on an uneven surface?

Hello,

I’m working on a 3d printable chocolate bar for my chocolate company (which I plan to use to make silicone forms). I have a 3d version of our logo which I was able to use to make a relief in the bar using solid tools (trim). I like the way it looks from above quite a bit.

My issue arises from the fact that I have an uneven surface onto which I’m applying the relief. The individual sections of the bar have a groove depth of about 3mm which I would rather not change. The way I’ve done it so far (trim) results in a depth of about 2.5mm in the logo relief at the highest points. However, this is too deep since the chocolate will then get stuck in the logo and break off. If I make a relief that is more shallow, I don’t get any imprint on the slopes going into the groove and lose definition of the logo.

What I’m looking for is a way to get 0.5-1mm depth of the logo all around. Actually, ideally the relief would only happen in the raised portions of the bar (including the slopes), leaving the bottoms of the grooves as they are. Is there any way to do this?

Thanks in advance for your ideas!

-Dave

ABC big bar moldv3.skp (4.3 MB)

First thing I would do is scale the model up by 1000 and work in meters instead of millimeters. This will help prevent possible tiny face issues. If your slicer software allows you to specify the import units as millimeters when you import the .stl file, you should be able to export the .stl file in meters and it’ll work fine.

Here I’ve trimmed the bar so logo is 1 millimeter (meter) deep. That works fine except that you lose a lot of the logo in the grooves. Is that acceptable?

I’m wondering if the logo could be raised instead of incised into the bar.

Thanks for the response! Yeah that is exactly the issue I’m trying to work around. I also tried a shallower imprint but I want to keep the definition on the groove slopes so I don’t lose entire letters of the logo. So I’m wondering if there’s any sort of extension or automation which would allow to only trim up to a certain depth.

I also don’t want to raise the logo. Both 3d printing and chocolate are harder to do with raised surfaces. The tendency is to have more breakage and less definition.

I’ll definitely take your advice about scaling! I have had issues with faces and hadn’t realized it would make a difference to to it on a larger scale. Thanks!

I’m working on another idea. Hang tight.

How about this? I now have the logo penetrating into the bottoms of the grooves without being deep on the raised areas.

I made the logo groups taller and trimmed the bottom with the chocolate bar. Then I moved the logo down 1 millimeter (meter) and trimmed the chocolate bar with the logo. Here’s the logo turned over.

And straight down on the chocolate bar.

As for the scale thing. check to see what your slicer will do with the file. Some slicers will handle it fine. I usually use i.materialise to check .stl files. Notice here I have your bar at 300 meters long and in the 3D print it would be 300mm long.


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I used a similar approach but Dave beat me on this one.

Click in sequence on the Scenes tabs of this SU file for ideas.

Relief text on uneven surface.skp (1.7 MB)

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Dang you guys are good. Simple, fast, and exactly what I needed. I only wish I’d been able to think of it! Thanks!

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I’m back with a follow up issue! Hopefully we can find a solution as easily as last time.

Everything appears to work perfectly when I trim the logo shape from the bar. Solid Inspector tells me everything looks good.


But then if I go to export an STL or even just save the sketchup file, a bunch of errors show up:

Am I doing something wrong? I’ve tried this several times in various ways and don’t seems to be able to get it to work right. It’s really time consuming to try to fix each of these individually.

Thanks!

ABC big bar moldv3.1.skp (3.7 MB)

Perhaps SketchUp’s Validity Check operation is damaging the model, due to very short edges? Do you get a dialog window popping up during Save that “Oh no” SketchUp found problems and it will “fix” them for you? That’s a clue that short edges are involved. If so, use the Dave method to edit the geometry at a larger scale:

I’m having no issues with your model. I can Subtract the logo from the chocolate bar, then save the file and all is still good. Then I am able to export the result as a .stl and it is the right size, albeit too big by 100mm, for my home printer.
I’ll attach the .stl for you to check.
ABC big bar moldv3.stl (938.9 KB)

Edit: I have just noticed in your screenshot you used Trim whereas I used subtract, perhaps that is the difference.
I also purged your model which reduced it considerably and I attach it.
ABC big bar moldv3.1Box.skp (728.2 KB)

Thanks for checking it out. You’re right that the STL seems to be working fine, so thanks for that! However, when I opened you Sketchup it had the same missing faces etc.:

Any thoughts on what that could be? Do I have some sort of settings issue?

Do you get a dialog window popping up during Save that “Oh no” SketchUp found problems and it will “fix” them for you?

No it saves normally, but then when I reopen the model or go back to look at it, it’s got a bunch of problems. I’m thinking that the saving might be a red herring and the problems were actually there from the beginning, it just takes a bit for the program to recognize them.

I’m going to guess you have it set to Automatically fix errors, which I have turned off.
Go Window/Preferences/General and untic the box I have highlighted.

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That did it! Problem solved. Thanks!!!

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