Getting Rough Surface when scanning smooth item

[Burl Source]

I tried to find any posted info before asking this question. I am sure it is probably happening because of operator error.

When I scan a smooth item (pistol grip) the scan ends up with a rough surface texture between that of rough concrete and asphalt. I am using a new machine (fall 2010) from CarveWright that came equipped with the scanning probe.

I have tried with each quality setting for the scan and all end up with the rough surface.
When I attached the item to be scanned to the scanning sled first time was with double stick tape. When that did not work out smooth I thought the tape might be allowing the item to move. Next scan I glued the item to the sled with CA glue so there was no way the item could move.

The image from the scan shows the rough surface and when carved it looks just like the image, rough. I would post the pattern image if someone is will willing to tell me how. I know this machine can do great stuff. Just need a little help getting the operator to function correctly.
Thank You in advance for your good help.

[mtylerfl]

Hello,

If the surface is VERY "textured" it is almost certainly due to movement of the item being scanned. Double-stick tape might not be holding the item firmly enough to prevent movement that you would be not be able to observe, but that's probably what's happening. Strategically placed hot glue might be better, but even some flavors of that is too "rubbery" to prevent movement. You may have to experiment.

If the surface is rather LIGHTLY textured overall, this is normal for any scanning operation done with a "touching probe". Only way to avoid that is with a laser scanner, unfortunately. Usually a light texture can be smoothed somewhat in the Pattern Editor, but use smoothing SPARINGLY...I see a lot of patterns where smoothing was overdone and the result looks a little like melted chocolate and the finer details are totally lost. I prefer to leave a little texture if necessary, then just realize that I can sand that out at finishing time after the carve.

Hope that helps. Holler if you have more questions. Also, you can post the MPW of your scan if you want us to take a peek at it to help you 'judge' whether the texture is normal or not.

[atauer]

One thing that I didn't read in either of the two posts so far concerned the flexshaft. When doing a scan, if you leave the flexshaft inserted into the truck, you can get some vibrations which will result in a lower quality scan. Also, sometimes when closing the clear cover, the motor tends to spin up for a split second, and if you have the flexshaft inserted, its going to spin the chuck, which in turn spins your probe, which could potentially rip the cables out of the probe.

[mtylerfl]

One thing that I didn't read in either of the two posts so far concerned the flexshaft. When doing a scan, if you leave the flexshaft inserted into the truck, you can get some vibrations which will result in a lower quality scan. Also, sometimes when closing the clear cover, the motor tends to spin up for a split second, and if you have the flexshaft inserted, its going to spin the chuck, which in turn spins your probe, which could potentially rip the cables out of the probe.

Good point, Alex! I forgot to mention that. Thanks!

[atauer]

You would be surprised at how many people are unaware of that. It may be a small tip, but it can make a big difference. The user just needs to make sure that when the flexshaft is removed, that the cable and spring do not fall out on the floor and get lost or stepped on. I have seen that happen a few times. Whenever I remove the shaft for a long period of time, I take a small sandwich bag and a twist tie, and place it over the end of the shaft. Seems kinda crazy, but I have yet to lose a core. We even ship them this way to prevent loss of the core. It works really well.

[cnsranch]

FWIW -

This isn't "technically" correct, but my take on scans it this -

In order to get an accurate scan, the probe has to be barely touching the item - the sensitivity has to be set lightly or we wouldn't get a good image. So, imagine as that the point of the probe is moving along the surface of the item to be carved, it picks up any variation in the item. That "jackhammer" sound we hear is the movement of the probe - it's almost like it's being dragged along the item. So, the resulting scan has minute bumps all over it - that's what the probe is picking up.

Bringing the scan into PE, and smoothing the scan ,very lightly, eliminates most, if not all of the bumpiness without losing the integrity of the scan. Be careful with smoothing, though - it doesn't take much to be too much.

A few years ago, MT did a write up on the probe here in the Forum - it's here somewhere, I just can't find it right now. It was an excellent explanation of what to do with the scan and how to refine it once it's been uploaded into Designer. Some of the points he made then don't apply now (one example is being concerned with the scan losing it's original size - the software now takes care of that), but it was a goodie.

Frankly, I don't know if that write-up was put into a Tips and Tricks edition or not, but if you can find it via searching for it, it's worth your time.

Final tip (learned the hard way) - immediately save the original scan as an MPW before making any changes in PE. That way, you can always get the original scan back if you're changes are too radical (that came from MT's many warnings about MPW's).

[Burl Source]

Here is an attempt to post one of the scans with the rough surface.
The piece scanned was smooth (sanded to 600 grit). The item scanned was superglued to the sled so no chance of movement or vibration. I am doing the scans with the flexshaft detached.

EDIT
Uploaded wrong file but this shows an accurate image of what the scan surface is like.

[AskBud]

Here is an attempt to post one of the scans with the rough surface.
The piece scanned was smooth (sanded to 600 grit). The item scanned was superglued to the sled so no chance of movement or vibration. I am doing the scans with the flexshaft detached.

EDIT
Uploaded wrong file but this shows an accurate image of what the scan surface is like.

Let's see if we can prove, or locate your scan problems.

Mount one of the pistol grips on the sled, but turn it 90 degrees.
Also, mount a quarter or larger coin/medal, that has highly defined features, nearby.
Program your scan to do both items at once. I use hot glue to mount my models.

My theory is that you will find the the marking on the grip will be about the same, and the coin/medal will be very true.

I assisted another member quite a while ago with a similar situation where he carved the praying hands. He cut away all but the hands, sanded, and re-scanned his carving. The resulting scan revealed all the grain of the wood.
I think you may find the same result.
AskBud

[cnsranch]

Couple things, Mark -

Pics below are your grips, and a scan I did a couple of weeks ago with no smoothing, etc. - right out of the scanner.

Mine (pic on the right) needs to be cleaned up in Pattern Editor, and with a little smoothing, I'll be good to go.

Yours (pic on the left) is a different story - you can see lots of definition on the scan, even looks like you can see just where the probe did and did not touch the surface.\


Make sure you check the set screws on the probe - mine had worked loose, causing the probe to be sloppy in the adapter.

Also, you may want (if you haven't already) to re-scan using optimum settings, that is, if the one you did was set to "good".

[Burl Source]

Ask Bud and CNS Ranch,
My apologies. I got tied up with other stuff and was unable to check the forum before now. Thank you for taking the time to give your good advice.
The set screws on the probe are tight. I was unable to loosen them. When I toggle around the probe point it does not always return to the same position. I am not sure if that is an issue or not.

Right now I am running a new scan with 3 different items glued in place. It will take about 3 hours but I will post the results when I see how it turns out.

Once again, my apologies. You were probably thinking "Darned new guy, asks a question and never checks back for the answers. "
Thank you for your help. It is very much appreciated.