In this topic I will let you in to some of my knowledge on methods, tips and tricks that spawn from my 9 years of scanning as a professional. I will try to adapt my techniques to what the revopoint scanners can do. This will be a less flashy, more technical topic.
Even though these scanners are classified as consumer level for hobby use, I believe scanners should be considered as tools with a specific capabilities and should be used accordingly. The end results in general are just as dependent on the users skills as it is on the tools used. As it stands right now, revopoint scanners have reached the point where they can closely match some industrial scanners if they are used in their optimal subject size and resolution requirement. Let’s take advantage of that!
Surface preparation for scanning:
Firstly you need to decide if your subject scannable as it is at all. As with all light based scanners, you generally cannot scan surfaces that absorb all or most of the light hits it or surfaces that reflect / bounce light off to a single direction, object that let most of the light through also cannot be scanned. Some scanners that have a very powerful light source with a high contrast ratio are exceptions, they are mostly line laser type scanners. Those scanners can collect data off of these type of surfaces, but it must be said, the data quality is usually pretty bad and require heavy post processing work, you cannot override physics. They rely on small surface imperfections that reflect enough light back to the scanner to register.
If your subject is scannable as it is, meaning it doesnt have reflective / transparent / darker than a deep grey surfaces, then you are good to go on that department. However if your subject has any of these properties, you should use some kind of scannig spray at least on the areas where they are problematic.
You must understand this: best case scenario for every light based scanners is a matte white surface on which the projection of the scanner is clear and is the highest contrast possible. Any deviation from this, as the surface gets darker and/or more shiny, the data quality / accuracy gets worse and worse. You can get the crispiest corners, smoothest flat surfaces with a full on white scanning spray coating all over the subject. A middle gray and slightly shiny object will give you a more noisy scan data that also misses some details here and there. A black or polished surface will only get you some scatter data where the scanner was pointing directly perpendicularly to the surface, or even no data at all.
Effect of colour / tone in scanning accuracy: Keep in mind when you prepare for scanning something: Every change in colour of the subject will create a shift in the perceived depth in the scanner. For example: lets say you have a perfectly straight and flat rectangular surface you want to scan, but one side of the surface is painted white, the other is painted dark grey (lets say the paint is uniform thickness throughout) You scan it and you will notice a line between the two areas in the scan data. You examine further and notice that one side sits higher than the other, even though they are perfectly level in reality. You can try this by scanning a printed paper. you will notice that the writing on the paper is still visible after you turn off the texture, even though the ink is so thin, that the scanner cannot possibly pick up that heght difference.
Considering this, if you scan for engineering purposes and need the highest precision possible and avoid false height measurements, you should cover the whole subject with scanning spray, until it gets an even colour/tone. (fully white)
If you want to have texture and precision is not at top priority, let say you want an item scanned for presentation purpose or use it as a digital prop in movie production, games… you have multiple options:
-If your subject is mostly scannable but has a shiny but not black and/or non-transparent surface: you can use a transparent matte spray: like the new aesub one, you can also use a hair lacquer spray, car wax spray if you want to clean them up later. You can use automotive matte varnish as well, if it being permanent is not an issue. All of these will retain the colour, but roughen up the surface enough to make the light scatter and be detectable by the scanner.
-If your subject is mostly scannable but has a black / shiny black / shiny transparent surface, you will need to use a light coat white scanning spray at least on the problematic area. If you want to retain the colours and tones evenly throughout the whole object without the scanning spray showing up in the texture, you need to apply an even light coat on the whole object. This will make the colours fade to be lighter, closer to white, but you can correct the texture colours back to be more vibrant later in third party image manipulation softwares like photoshop.
Nice introduction to scanning in general @lajoosh , but you need to go more specific , as not all scanners works the same way , so the professional guide not always works with Revopoint Scanners .
Let me add here that Scanners that use Infrared Light for scanning can scan any color objects from white to black , the difference is about the surface proportions , for example black silicone will absorb infrared light , but black cotton will not .
Black velvet will absorb Blue light like from Example MInI but it will not absorb Infrared Light .
POP series and MINI can’t scan black plastic , but Range scanner can .
So let’s get more deeper on subject regarding specifically Revo point scanners as not all dogs names are MAX .
And here are huge differences between them .
Also when using MINI or POP series scanner for scanning smaller objects , the scanning surface color should be more of light gray if possible than pure white to create better contrast on close up scans , if the object is too white it will infuse noises and miss fragments while scanning as the exposure if the software can only be set to specific value .
Thanks! The reason I’m generalizing a bit is because the things I say I want them to be applicable to all structured light scanners. Ever since I started scanning, I have worked with white light scanners 95% of the times, so thats what I know best. Different kind of light sources will have more or less influence of the scanners overall capabilities. Different materials might be able to scan better or worse, based on how they reflect visible vs infrared light and not just based on their visible colour, true. However you can think of materials that absorb most of the infrared as being black in the infrared spectrum. Regardless of their visible colour. 
By the way, it is interesting, my range seems to be having trouble scanning things that are black in the visible range, even though it scans geometry with IR.
Also the reason why scanning sprays are mostly white is because on most scanners it is easier to dial back the light sensitivity on the scanners cameras, rather than trying to overpower outside light sources by the projector while projecting to a darker surface.
I will try to test with pop when I get the chance, regarding grey vs white surface preparation. What you are describing, to me it sounds like you get over exposure when you do a closeup. Is the depth sensor slider set all the way to the lowest setting? If you cannot get the exposure low enough when using white surface and you get overexposed image, then it makes sense to use a grey one instead. Anyway, I think this is a deeper technical detail, it really depends on the actual scanner used.
That is all ok @lajoosh , don’t take my reply in a negative way …
Things is that most of the users have access to generalized options online and almost none of it for actual Revopoint scanners that works a slightly different .
Range can scan almost all black surfaces as long you keep the proper distance and exposure settings . That include Black Plastic, Black Silicone , Black PVC and other synthetic materials that other scanners from Revopoint can’t scan .
The reason I dismantled my scanning station as it was no more functional because everything was scanned .
Anyway please continue your thread with informations and findings …
Scanning sprays
From expensive to cheap ones, these are the methods I used over the years. I will list only those brand products that actually have a benefit as a scanning specific spray, over just being a white coating, the rest will be easily available household solutions.
#1: AESUB orange: White coating that vanishes over a longer period of time. Gives a thick and even coat if you know your way around rattle cans, although particle size is larger than you might expect. Dries fairly quickly in seconds. I suggest using this from medium / desktop size subjects to large ones, since the coating thickness can cause significant dimension increases on small objects and also because this coating will last a fair bit which you don’t need with small, quick to scan subjects, but you do need the time to do larger ones. Use it only if the situation calls for surface coating that don’t require cleanup afterwards, like washing and mechanical cleaning is prohibited. The spray cans are solvent based, contrary to the marketing materials, they might harm some plastics if you spray them from too close or too much at once. Ask me how I know!
#2 AESUB Blue: White coating that vanishes over a shorter period of time. Gives a thinner and very even coat. Dries fairly quickly in seconds. I suggest using this from medium / desktop size subjects to small ones. Significant dimension increases only occur at very small items. This one vanishes much more quickly than the orange so you need to be prepared to do the scanning efficiently. Use it only if the situation calls for surface coating that don’t require cleanup afterwards, like washing and mechanical cleaning is prohibited. The spray cans are solvent based, contrary to the marketing materials, they might harm some plastics if you spray them from too close or too much at once.
#3 AESUB Transparent: A transparent coating that vanishes over a shorter period of time. Gives a thinner and very even coat. Dries fairly quickly in seconds. I suggest using this from medium / desktop size subjects to small ones in case the colours are more important than absolute accuracy. Significant dimension increases usually dont occur since you only need a very thin coat, just to dull up the shiny surface. Use it only if the situation calls for surface coating that don’t require cleanup afterwards, like washing and mechanical cleaning is prohibited. The spray cans are solvent based, contrary to the marketing materials, they might harm some plastics if you spray them from too close or too much at once.
#4 AESUB Green: White coating that vanishes over a period of time. This one comes in paint can form, that you have to spray on with suiable equipmet, like electric spray guns or compressed air paint guns. It is a better value option if you have the equipment to work with it. I suggest using this for large size object, like cars. Significant dimension increases only occur at very small items. Use it only if the situation calls for surface coating that don’t require cleanup afterwards, like washing and mechanical cleaning is prohibited, or if the object is too large and/or complex so a manual cleanup just doesn’t worth it.
#5 Any generic welders white crack inspection developer sprays / crack tester sprays: White permanent coating that can wash off easily with water. Dries extremely fast. Gives a very nice even coating and covers well with even a thin coating. If you spray it very lightly, you can have a perfect even coating while the colours can still bleed through from underneath. Particle size is so small that you generally don’t have to worry about dimension change in case of small objects. This one is a must have if you plan to scan small precision metal parts but it is also the best tool when you need to scan larger desktop size metal parts with precision, like injection mould toolings. It can also be used on large subjects (car size), but in that case it is not the most cost effective solution, since you don’t necessarily need this perfectly even coating. This spray is very sensitive to any liquids that might be on the surface, for example: if the surface has some slight oil stains, the coating will be almost transparent there and remain that way. Be aware, that this spray is acetone based so it can harm a couple of plastics and rubbers. Do not use this indoors for large parts, or the fumes will get you!
#6 Erasable chalk marker sprays: The perfect balance in all aspects for general use. White coating that can wash off easily with water. Comes for a fair price. It gives a thick coat that covers really well with a bright white matte finish. It can work with slightly oily surfaces and on rust as well. It is water based so it is safe for any plastics. Does not create bad smells or harmful fumes. Dries in a managable amount of time, measured in minutes to a half hour. Not really suitable for small objects, because the paint can splatter a bit and can be pretty thick. I recommend this from medium desktop size to large size subjects.
These were the products I use daily as a professional.
And now the scanning junkie stuff:
#7 Baby powder suspended in a solvent
Baby powder / talc powder can be mixed up and suspended in brake cleaner liquid / acetone / denaturated alcohol / cleaning benzine. The suspension can be used in electric spray guns, compressed air spray guns and pump pressurized spray bottles. These dry very fast. The coating can be a bit patchy and splattered to some degree, depending on what spraying method you choose. You have to constantly shake or stir to keep the talc particles suspended. Being solvent based, they can harm plastics and you as well. The fumes and smells will be a problem, so stay in a ventilated situation with these. I recommend using them for large objects only, where you are not after the smallest details and perfectly smooth scanned surfaces.
#8 Tempera paint
You might also recognise this as childrens art paint. Comes in bottles in paste form. Water based, safe for plastics and also not a health hazard in any way. You have to thin the paint to a milk like consistency, maybe a hair thicker. You should also mix in a bit of dishwashing soap to reduce surface tension, for an even finish. This paint can be used in electric spray guns, compressed air spray guns and pump pressurized spray bottles. Again your coating quality will depend on the chosen spraying method. This dries slow as you can expect, but it is a really cost effective solution for for really large subjects done in quality. This is also the cleanest and safest to use and even smells good, both when applying and washing off.
#9 Hair lacquer: A thin, matte-is transparent coating. This one works well if you want to scan small shiny objects with colour. Dries very fast. Buy the cheapest hair lacquer, it doesn’t matter! You have to spray from far enough so that the droplets don’t fuse on the surface but stay as little balls. This will create a matte surface for you while the colours will come through perfectly. Being water based, they are safe to use on any surface to my experience, and it washes off with water fairly quick.
#10 Automotive spray wax: Particularly useful if the client is afraid you might damage the paintjob on his car by a regular scanning spray. If you apply this correctly, you can have a semi-white, fairly even, matte surface after drying. You can even adjust how much colour bleeds through by how much you coat the surface. After you’re done scannig , you can just finish up with nice full waxing job on the car, the client will be happy.
#11 Dry shampoo: Gives a thick white coating with fairly large particle size. Not the easiest to use if you want to get an even coat. Not recommended if you want to scan small objects with precision. Coming in small bottles, they are a bit wasteful to use, but can be handy if you only scan small to medium size objects on the go. Also it can be a last resort option if you are in a pinch, as these can be found in any grocery or beauty stores, ready to use immediately. In general, you should use erasable chalk spray instead of this, they come in similar price for the same amount but the chalk spray is better overall.
#12 Baby powder suspended in water:
Baby powder / talc powder can be mixed up and suspended in water with a generous amount of diswashing soap added in. The suspension can be used in electric spray guns, compressed air spray guns and pump pressurized spray bottles. This one dry slowly and multiple coats may be necessary. The coating can be a bit patchy and splattered to some degree, depending on what spraying method you choose. You have to constantly shake or stir to keep the talc particles suspended. Being water based, they don’t harm plastics neither you. I recommend using them for large objects only, where you are not after the smallest details and perfectly smooth scanned surfaces but you want the absolute cheapest way to get the subject scannable.
#13 Automotive or household rattle-can paints:
Light grey primers / fillers can be a particularly great option if you plan to paint the object after scanning anyway. Matte white or grey acrylic top coat spray cans work really well too in case the object is a throw away after scanning, or its just simply doesn’t matter if its painted. These create a nice even matte coating as expected, being spray paints. For safety, as usual with any paint, refer to the SDS!
This post supposed to be a general overview of the options available that I actually know to work and used. I may have more or less experience with each particular product / method. Your mileage may vary. For your own and the scanning subject’s health, always read the safety datasheet of the product you use and if necessary, do test coatings on less critical surfaces first!
I would reccomend Corn starch instead of Talc powder.
Not only it is safer to use in case of accidental inhaling, but it is easy to dust off with air or wash with water and can be used on skin also
Corn starch can be used with isopropĂl alcohol or rubbing alcohol since it dows not mix with any of them
Potato and definitely Rice starch .
I like to use Zinc Oxide
on fine metals like rings, dental parts etc.
How does corn starch behave when mixed into water and sprayed over a surface? How is it after drying? Asking this because the very thing I didnt like when using talc powder is that it does not dissolve in water so it had a tendency to clog up everything if I wasnt careful.
I’m looking for to cheapest and most easily accessible solutions out there!
The most used in the industry is Rice starch , however no matter what starch you use, don’t use with water, only with isopropyl alcohol or rubbing alcohol .
You can mix starch with alcohol and use even a brush to apply layer on a surface or partial surface where it is only needed .
You can easy brush off after usage without the need to wash the object and rice starch will give you are 3 microns layer only compared to 15 microns when using AESUB Blue 3D spray .
You can create your own rice starch by grinding a rice in a coffee grinder/ space grinder , the cheapest .
I have never before landed on the corn starch or rice starch earlier. You learn something every day. Thanks!
Thanks, I had just asked about a comparison between talc and starch when I came across your post. Thanks for the info, I’d definitely try it
I thought some of you might be interested, not everyone has a camera without IR filter.
This is how the Revopoint POP3 3D scanner infrared structured light projection pattern looks like using an IR capable camera.
I would not mix it with water , it will activate the rice starch … bacterial situation about to happen… only with rubbing alcohol and very fine Rice starch , use with spraying bottle and just frost the surface slightly not over painting it , not need to be white surface , clean with a dry brush or vacuum cleaner …
For my MINI 2 showcase ( Revopoint MINI 2: Here's what this new high-precision 3D scanner is capable of! ), I tried to improve my coin scanning technique. And I think I stumbled upon an interesting trick.
Left: standard 3D scan, AESUB orange
Center: single shot mode (I took inspiration from @PUTV ), AESUB orange
I did a few attemps with potato starch but I was not satisfied (I need more practice, I end up creating an uneven coating), so I reversed the issue: what if, instead of coating the coin, I created a twin of the coin that could be scanned easily?
- I used silicone and created a mold of the coin (the brand and reference are in the article above, near the end).
- I then poured plaster in the mold.
- and I scanned the end result.
Right: silicone mold, plaster coin, single shot mode.
To be honest, I wasn’t expecting much of this approach, I was afraid I would lose quite a lot of detail, but it does seem to work.
And I think I could get even better results by using finer, whiter plaster.
The plaster model will be always better , because it reflect the true surface without being reduced with 3D spray .
Nobody really uses any kind of 3D spray when scanning very fine details because there is always lost of details .
I did this test long time ago also with natural Face vs plaster Face and of course the plaster will always produce amazing results . That how we scanned people’s faces in the late 90’s for Animation.