# How do I prepare an image for CNC engraving?



## HuntleyBill

I need help with a couple of things. Ultimately, I would like to take photo images and engrave them onto wood or plexiglass. First, I would like to learn how to prepare a photo to be engraved. How to prepare the photo so it comes out nicely when engraved. Currently, I have Inkscape and Gimp.

Secondly, I would like to use my CNC router to engrave with. I see lots of tutorials on laser engraving but I DO NOT want to laser engrave. I intend to use my CNC router and an engraving bit.

I'm sure others are doing this but I was hoping I did not have to go through a steep learning process if someone else already knows how and tutorials etc have already been done. I've looked but can't seem to find much for CNC router engraving.

Hope you folks can guide me.
Thank you for your help
Bill


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## DS

do you hear crickets??? ;-)

There are only a few programs that can extrapolate depth-of-cut from Grey-scale images.
I don't have any experience with this, but it has been done before.

I wish I could help more, sorry. My fuzzy memory tells me that someone on LJs showed this before, so, you might try your hand with the search feature on this site.

Good Luck


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## ArtMann

The Vectric company sells a product called PhotoVcarve that will do what you want to do if I understand you correctly. There are a few shareware type programs that will do what is called halftoning. One of those might be useful as well but you are going to have to do a lot of conversion work to get something useful. Gimp and Inkscape are free. I don't think you are going to find any free programs that will do what you want without a lot of finagling.


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## Desert_Woodworker

> The Vectric company sells a product called PhotoVcarve that will do what you want to do if I understand you correctly. There are a few shareware type programs that will do what is called halftoning. One of those might be useful as well but you are going to have to do a lot of conversion work to get something useful. Gimp and Inkscape are free. I don t think you are going to find any free programs that will do what you want without a lot of finagling.
> 
> - ArtMann


+1


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## oldnovice

I believe there is a video tutorial on YouTube that uses Fusion 360 from Autodesk. 
There are also some sites that convert photos into 3D images, positive or negative, out of or into the material.


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## ArtMann

I have never seen a credible service, free or pay, that will automatically convert 2-D photos into true 3-D vector imagery. It is very hard to generate information out of thin air. Would you kindly post a link?

I don't think 3-D is what the original poster is looking for. He said "engraving" and not "carving".


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## oldnovice

There are videos for Fusion 360 but they also use some other software to get the results desired!
Embossify is one I have used!
One I have not tried is from Grabcad
This one from Ransen I just found the other day.


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## HuntleyBill

Yes, there is a product called photoVcarve but it does not do photo conversion well at all. I've also tried halftoner with no luck. The first picture shows a photo that I would like to engrave. The second photo is what photoVcarve did to convert it, the third picture is what the engraving looked like from my cnc router, and the 4th picture is an example of what I would like to do. As you can see, NOT a good result at all.


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## ArtMann

What the web page shows being converted into a 3-D image bears no resemblance to a photograph and the software product will not do what the original poster wants. The same is true for the other links you provided. They all use a simple minded "darker equals greater depth of cut" algorithm. That is a far cry from turning a photo into a 3-D image. That is not the way real photographs work. I know of a guy who does this kind of conversion for a living. He used to hang out on the Camaster forum. He probably makes $50+ an hour doing it. If it were as easy as just scanning a photo and pushing a software button, his trade wouldn't exist.



> There are videos for Fusion 360 but they also use some other software to get the results desired!
> Embossify is one I have used!
> One I have not tried is from Grabcad
> This one from Ransen I just found the other day.
> 
> - oldnovice


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## ArtMann

I have seen several lithographs similar the one you posted that were created in PhotoVcarve. I hate to be blunt but just because you can't make the software do that, it doesn't mean that nobody can. There are pictures all over the internet of similar projects done with this product. Here are a few . . .

https://www.google.com/search?q=photovcarve&tbm=isch&tbo=u&source=univ&sa=X&ved=2ahUKEwi1xvzekdLcAhVD61MKHa8MA5MQsAR6BAgAEAE&biw=1920&bih=947

Just be advised that you will never get the same kind of results you will get with a laser that has much, much finer resolution.



> Yes, there is a product called photoVcarve but it does not do photo conversion well at all.


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## HuntleyBill

Thanks ArMann. I do understand what you are saying. You stated it yourself that they use a darker equals depth algorithm to get the result. I am not trying to do that but instead to engrave the image into a substreight. Even using a laser, the image still has to be converted so the laser can engrave it.

As you mentioned about your friend who converts these images for $50+ an hour. That kind of answers my question then. PhotoVCarve can't do what I was asking in my original posting. Please don't misunderstand me, I am not saying PhotoVCarve is bad software, I'm just stating that I don't think it can do what I would like to do.

What it seems I need to do then is to find out what software your friend uses and learn how to use it. Then maybe I CAN get the results I am looking for.


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## oldnovice

*ArtMann*, I have to agree that the process used by most of these conversion programs are based on grayscale and are not truly a 3D conversion but I haven't found anything better!

However, Embossify did a fair job on one of my photograph but I haven't tried another and it just could have been my subject matter.


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## oldnovice

Just for grins I did a little surfing on YouTube and found some interesting videos using Photo V carve and DXF halftoner.


















The results are decent for what each can do!


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## JAAune

If using a laser, all you need is photo editing software like Gimp. There is a learning curve but it's much easier than doing true 3d carving on a CNC.

I've done simple, low-relief engravings using pictures but not ordinary pictures. I took a picture of a carving in a dark room using a single light source pointed at the object I needed to duplicate. Four black and white pictures - each with the light coming from a different direction - were then merged to give me a crude, black and white height map. The result after some editing was pretty good but not nearly as good as 3d-scanning.


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## OG51

I use my cnc machine almost exclusively for engraving and carving.

There is no easy way to get perfect conversions of 2d images into true 3d (2.5d). At least that I am aware of. It is a conversion of gray scale to a depth cut measurement (bas-relief). It can be done but it takes a bit of skill to do it. I tried to learn how to do it but gave up on it. I was not very good at it.

There are different softwares that can create depth/height maps with mixed results. Look at Shadermap Pro for an example but there are several programs that can get similar results. Do a search for bas-relief software.

As JAAune mentioned, there are also different techniques to created depth/height maps.

Another option is to build 3d models that can then be converted to carvings or engravings. Very challenging to learn but super rewarding once you get the basics. Here are some of my projects.

http://lumberjocks.com/topics/269465

Lithophanes are a different matter. As long as you have a good picture you can get decent results. The material has to be thin enough to allow light through so the thickness of the material can create the light and dark of an image: Shallow cuts (dark) deeper cuts (light).


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## HuntleyBill

Thank you OG51 I will check out that software. I have been trying lithophanes on corian with good results. I'd like learn how to get the engraving on acrylic to work much better and maybe put the caring on the shelf for right now.


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## wichman3

A couple of pointers. (I have scanned, converted and lazed pictures at work).
1. know your equipment. What is the resolution that your cnc uses. 300dpi is common, this is the resolution in magazine pictures.
2. scan at the resolution your machine will use, any other resolution will force the software (perhaps the hardware) to translate, without your input .
3. scan in the color mode that will be the final output. The fewer times the image has to be modified the better.
For example, the image you first show was a color image at 71 dpi, that's a lot of conversion for the software to do, without your input.
And finally, practice, practice, practice. Break up your test piece(s) into grids, that way you can adjust settings and compare side by side versions until you get what you are after.


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## HuntleyBill

Wow…thank you. Those are great tips. I don't know what the resolution of my machine is. Mine is a home built CNC but I guess I could find out.

A lot of the images are already digital so I guess I could convert the images to B/W. Would that make the dpi easier for the software?

It seems to me that engraving acrylic, I would need to figure out how to get the software to engrave the dark areas and NOT engrave the light areas to get that to look good.

Thank you for the suggestions.


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## oldnovice

I believe that it won't be long before someone designs a "layer" digital camera much like Keyence has for the 3D measuring system.
A camera that takes a selectable number of photos, each at a different depth "layer", of the same image to achieve a level of 3D. All layers would be photographed quickly, much like taking a single photo.
It would be a step towards 3D laser measurement but less costly and more readily available.


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## wichman3

*A lot of the images are already digital so I guess I could convert the images to B/W. Would that make the dpi easier for the software?

Converting to B/W will not change the dpi but it will reduce what the machines have to interpret for you.

*It seems to me that engraving acrylic, I would need to figure out how to get the software to engrave the dark areas and NOT engrave the light areas to get that to look good.

You should be able to have the graphics program "invert" the B/W to W/B.


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