Fairy godmother

[myxpykalix]

Why do greyscale bitmaps seem to be more pixilated when trying to convert them into stls? The bitmaps i have found even though they are over 1 meg in size and 1000x1000 always seem to have lots of artifacts in them.
The general consensus to me is naturally they are too small and like normal photos the higher your "dpi" is the better quality photo you will have so it would seem the same would be true for the greyscale bitmaps.

However how would you boost the resolution when converting a stl or saving as a bitmap?

This "fairy godmother" is just a bmp changed to a jpg used as a example file to illustrate my point. Boy wouldn't it be nice if we all had "fairy godmothers"?

[bob_s]

What Brian at Vectric explained to me was that these gray scales are 8 bit - they use 256 steps to describe black,0, to white, 256. The interrnal workings of Aspire and many other 3d systems use 16 bit or 65,536 to describe the Z or height value, resulting in a much smoother surface with less visible artifacts.

[myxpykalix]

Since i don't use that pgm my photo editing program only saves as "8-bit greyscales" so is the key to find a photo editing program that saves in 16 bit? And do programs save in 16 bit?

My program is photostudio 2000 so its 10 yrs old but works simple for me..

[lcolburn]

Photoshop will save in 16bit, but of course it's really expensive. I'm not sure if Gimp supports 16bit, but that might be worth trying as it's a freebie.

[navigator7]

Boy wouldn't it be nice if we all had "fairy godmothers"?

In the immortal words of Astro: "Rutt Row!
What are the Jetsons going to do now that you have absconded with their fairy godmother?

Why save as a bitmap at all?
Can you go straight to pngs?
Even jpegs.
I believe saving as a bitmap creates the very thing you are trying to avoid.

[myxpykalix]

If i remember correctly a bitmap is a uncompressed format whereas jpgs and others are a compressed format which in turn helps create the problem in the first place.
Chuck...you need to go back and brush up on your cartoons...in the 60's version there was never any fairy godmother. Maybe you sre thinking of the flintstones "the great gazoo".

[navigator7]

If i remember correctly a bitmap is a uncompressed format whereas jpgs and others are a compressed format which in turn helps create the problem in the first place.
Chuck...you need to go back and brush up on your cartoons...in the 60's version there was never any fairy godmother. Maybe you sre thinking of the flintstones "the great gazoo".

Highjack!
I know exactly the problem you are describing and trying to avoid. When I did 3D printing, I ran into the same problem. My work-around was to stay away from the bitmap altogether and use PDF's, PNG's or import/export from various cad programs.

Command+Shift+4 on my Mac produces a png of whatever I drag my curser over. From there I can increase the dimensions of the bitmap without all that jagged sawtooth stuff.

Fairy Godmothers are just something you don't forget! If your fairy godmother was cast onto a set.....it would be the Jetson's...don't you think?
She'd ruin Elroy.

[bob_s]

Jack
it doesn't matter what program you use, there is no way to import anything but an 8 bit image. There doesn't seem to currently be be a solution to this problem. I have checked information from all of the common 3d programs, and none will allow the us to import high bit depth gray scale depth maps.
The only thing that seems to help is to import the gray scale into Aspire and then smooth it, either globally when it is in your working model, or manually with the sculpting tools. Both methods help, but both will lose important details.

[ssflyer]

Bob,

There are a number of programs that will import and export 16 bit greyscale images. Photoshop CS5 will even allow editing and writing 3D meshes... I'm also pretty sure that 3DSMax works with 16 bit height-maps, among others. Maybe I'm misunderstanding your comment?

Ron

[gc3]

This "fairy godmother" is just a bmp changed to a jpg used as a example file to illustrate my point.


Boy wouldn't it be nice if we all had "fairy godmothers"?


Yes it would.

[mims]

Artcam will definitely import and make a relief from a 16bit image. If I recall correctly, there are a few ways to import images and make reliefs from them, but only one way to correctly import 16bit.. it's a bit confusing. There was a button on the layers area that said create new layer from image, or create relief from image, and it would read 16bit images and properly give you a nice smooth relief. If you simply imported an image into the workspace or used some other image relief function in the program, it would always seem to convert to 8 bit first and give you a 'choppy' relief.

[myxpykalix]

Eric,
If artcam will import a 16 bit thats great but i still need to figure out how to save it as a 16bit image first. Then what version imports the 16bit? The version i have access to is Artcam 2008 and i seem to recall that someone said that version is only capable of 8 bit, but i could be wrong.

[mims]

sorry, not sure of freeware or other programs that will open/create/save 16 bit files, though they must exist. I have Photoshop and of course it does it with no problem. Of course, if a file is 8 bit, saving it as 16 bit will do nothing to add info/gradients to the file.

As for Artcam, I have used the 2009 version a couple times and it can create reliefs from 16bit images. Not sure about 2008, but I saw a post on the forum about all versions after Artcam9 could import 16bit and I think 2008 came out after v9.

[adrianm]

Not sure how it's done in other programs but I create 24 bit greyscale PNG files in Xara quite often.

Take the required picture. Draw a black rectangle over it. Apply a 0%, saturation transparency filter to the rectangle. Export as a truecolor PNG.

[myxpykalix]

adrian,
could you take a greyscale picture you have created in xara as a 24 bit and send to me, it can be anything. I would like to do some comparisons. Send to myxpykalix@hotmail.com thanks

[adrianm]

adrian,
could you take a greyscale picture you have created in xara as a 24 bit and send to me, it can be anything. I would like to do some comparisons. Send to myxpykalix@hotmail.com thanks

Done. Hope it helps.

[bob_s]

sorry guys, but I believe that you have created is a 24 bit rgb file with all rgb values being equal so it looks like a B&W. it still has 0 to 256 steps from black to white. This is very different from a 16 bit file, or 48 bit if RGB, which has 65 thousand steps from black to white.
Just converting a 8 bit gray scale to 16 bit will not help with the lumpy steps unless you blur it after the conversion.
It is all a bit confusing. The way it looks when cut will be very dependent on how the 3d programs handle the file internally, and the size of the cut piece. If the piece has only a 1 inch difference in height, then the 256 steps of the gray scale will result in 4 thousandths per step. Is this visible? the "resolution" of the final output, your cutting, depends on your wood, bit, step over, how much of the black to white range was used, etc.

[adrianm]

You're almost certainly right. I make them greyscale in that way for "arty" shots rather than importing into Aspire or Artcam. I'd be surprised if those programs didn't do something very similiar when convering colour photos so it probably won't add any detail.