Contour map gray resolution

[cycollins]

I wasn't trying to be obtuse. Usually, I try to tailor my answers to the asker. The originator of this thread was santhony94107, who identified himself as a programmer, working on a rewrite of an old Amiga application. I was using short-hand for someone who was in the midst of a problem space that I know pretty well.

The idea is simple - make your patterns, using the highest precision (bit-depth) possible, then use a good image processing application like Photoshop to scale back down to 8-bit grayscale (the format used by the CW machine). Photoshop will use a collection of the mid-tone grays at every level in a noisy, probability-based pattern to simulate the grays that are missing between "steps" of the 8-bit gray-scale color space. This noisy stuff will have at least the superficial effect of breaking up the stair-stepping phenomenon, which nerdy folks like me call aliasing. ("noise" to geeks like me means "randomness", not ugly sound.)

The tricky bit is getting the data into Photoshop if it didn't originate there (which in the case of santhony, it didn't). Santhony's data was generated by a program he was writing, so he needs to write it out in a file format that Photoshop can read in, without dropping it down to eight-bit grayscale. Grayscale images with more than eight bits of precision are a relatively recent development, and there are only a few file formats that have any way of expressing them - that's why all the talk about TIFF and DX texture formats, etc. I was trying to suggest some easy file formats I knew about that he could use in writing out his data, because .bmp (the format he had his example pattern in) won't do it. TIFF, PGM and a few others will. The other stuff about "endianness" was just geeky heads-up about the pit-falls of trading binary data between computers with different microprocessors.

While I was writing all of that however, I realized I should be doing the same thing for the figural art projects I'm doing, at least when they're bigger than a candle-stick.

Cycollins

[DocWheeler]

Cy,
You don't have to appologize, it made me feel good that I actually understood about 10% of what you were saying

[mtylerfl]

Hello Cy,

No apology necessary of course, as you were directly responding to a fellow programmer with terms especially suited to the topic at hand in your original post.

Thank you for your excellent explanation. Your most recent post used terminology that even I understand!

Thanks again -

[santhony94107]

Thanks Cy for the info and suggestions. My machine has been on a round-trip to Texas for a couple of weeks, and I haven't visited the forum for quite awhile. The last pair of back pieces I carved for a new guitar order (a tenor archtop, my 30th instrument) worked out really nicely just by blurring the stair-stepped image that I had originally used. It required very little sanding to eliminate any traces of the carving process.

By the way, Collins Guitars are really, really nice. Do you use the CarveWright for backs and tops too, or for parts like the tailpieces?

[KHP]

When importing from Illustrator to Photoshop using a high DPI setting (600dpi at least) will make the gradients VERY smooth, no more need to use blur. I am using 1200dpi at the moment which takes a long time but gives very smooth contours indeed.