Learn the Basics of 3D Scanning in Outdoor Conditions

Introduction

I am a 3D Scan Artist. I have been actively freelancing and accepting new job offers in this direction for over two years. Since writing my previous article, I have acquired more equipment and experience with various objects, which has allowed me to move my workflow from home to the street. For a 3D Scanner, the most important thing in its work is to find unique and beautiful objects to scan.

It is also necessary to be able to meet the customer's needs in all categories of objects, you will have fewer opportunities to take on the best orders. Over time, the number of objects that I could easily bring home has decreased dramatically, so the question arose of scanning them directly where they are located.

How to Prepare for Street Scanning?

First, I would recommend you read my previous article on home scanning, which describes the basics of scanning objects. The scanning method itself will not differ on the street, but the conditions in which you shoot will be different. You essentially have no room for error, so I recommend that you first master scanning at home and then move on to the street.

This way, you can quickly find mistakes and calmly make the necessary changes to your shooting approach. Outdoors, this will take much longer, and the experience will be very frustrating, because no one wants to go back to a steep hill in the forest to reshoot.

Gathering Equipment

Any scanning outside the home or studio often involves a long shoot throughout the working day, because it is much more time-efficient. There is no point in going out to shoot just a couple of items when fulfilling an order. Prepare for a long shoot with as many scans as possible at a time, so you can have a good block workflow where you first shoot all the items and then sit back and process them.

Running back and forth between the items and your home will only waste valuable time and energy. To ensure that a long shoot is successful, you need to take care of all the equipment in advance. Below, I will describe the main items and some tips on how to use them.

Comfortable Backpack

If you go out to take photos close to home, you may not notice much difference between a comfortable and an uncomfortable backpack, but when you have to travel with it, take flights, or arrive at a beautiful village, get out of the car, and walk for a long time, you will definitely feel your back getting tired from carrying all the equipment.

A backpack should be comfortable and spacious so that it can hold all your equipment, and you don't have to carry anything extra in your hands. Save your strength, because you will need it when shooting. As someone who often goes hiking and climbing, I can assure you that spending money on a comfortable backpack is the best investment you can make for the future.

Choosing a backpack is a personal matter, so I recommend going to your local store and trying them on. Also, don't forget that the backpack should be waterproof. The equipment is very expensive, and you don't want to get it wet unnecessarily.

Extra Batteries & Lenses

The main thing for long shoots is to have spare batteries for both the camera and the flash. I use a Godox AR400 flash and a Sony Alpha 7III camera. In my experience, three batteries are enough for the flash and two for the camera. If your camera is higher-end than mine, such as a Sony Alpha 7rIV, you will need three batteries, as it consumes more power.

Different lenses with different focal lengths are better suited for shooting different objects. Some lenses can change the focal length, but I recommend buying fixed lenses that do not. With variable-focal-length lenses, you can accidentally change the focal length slightly while shooting, which can greatly spoil the scan. All photos for a single object must be taken with a fixed focal length!

For example, for pano 360 (I recommend learning how to do them, it's good extra work), you need a lens with a fisheye effect. This is necessary to capture the entire space around with fewer photos. For corridors or other narrow spaces, you need a wide-angle lens, as long-focus lenses simply cannot focus at such a close distance.

For medium-sized objects, such as stairs, gas cylinders, road barriers, large snags, or boulders, a lens with a focal length of 45mm will suffice. If the objects are very small, such as bread, vegetables, etc., then 30mm will be enough. For low buildings or parts of the landscape, you may need a lens with a focal length of 75mm or more.

This way, you won't lose too much quality due to the difference in distance between the bottom and top of the object. For rocks and multi-story buildings, a drone is usually used because it is impossible to capture their full height from the ground due to the large angle of view, which greatly reduces the quality and does not allow the entire surface to be captured correctly.

In general, this is certainly possible when rendering a scene from lower angles, but if the camera flies near a rock or covers the entire rock in one frame, the difference will be obvious.

Tripod & Camera

In most cases, it is more convenient and faster to shoot handheld, but sometimes you need to set a longer exposure to get enough light, or shoot something you cannot reach without a tripod. When using a long exposure without a tripod, all frames will be blurred, which will ruin the scan.

Avoid this! Also, when shooting a 360 pano, it is important to take photos while standing in place and turning a certain number of degrees after each frame. This is impossible to achieve without a tripod.

Of course, we cannot forget the most important thing: the camera. You can buy a small separate case for it that fits in your backpack, in which, in addition to the camera, you can put the lens, batteries, necessary connectors, consumables for cleaning equipment, etc.

Distributing items to designated locations will make it easier to find the equipment you need and provide additional protection against unnecessary wear and tear. This type of organized storage will help you avoid losing equipment on location and forgetting something at home before you leave.

Filters

Essentially, you only need two filters: a polarizing filter (CPL) and a neutral density filter (ND). When photographing large objects, you usually cannot use a flash, as you would need either an extremely powerful flash or a long exposure time. In the first case, you would have to carry huge spotlights with you, which is objectively impossible. In the second case, the surrounding light will be too visible in the photo, and the cross-polarization effect will simply disappear.

But using just one CPL filter is also useful. It cannot cut off all reflections in this configuration, but it can cut off a small part. A darkening filter is needed for shooting 360 panoramas when you need to darken the sun. I don't have much experience with this yet, but I think I could write an article on this topic later.

Flash

I put the flash in my backpack without an additional case, as it is already large and would take up even more space inside the case. Also, don't forget about the polarizing filter for it. It is not sold separately. You need to print it yourself on a 3D printer and order the necessary polarizing film to make a CPL filter by hand. Ready-made files for 3D printing with a filter frame can be downloaded for free on many specialized websites.

All Sorts of Small Items

Here you can think about a color checker, a tape measure for measuring and recording the actual size of an object, various portable chargers and power banks, memory cards for your camera, etc. You can also buy a small folding chair that you can easily carry with you. It is needed so that you can place an object on it and take pictures comfortably, even where there is no good flat surface for this.

It will also make shooting easier compared to shooting on the floor, because you won't have to bend over too much to get good shots, which puts a lot of strain on your back and is generally harmful. I recommend finding high surfaces where you can shoot comfortably, if possible. In general, the rest of the equipment depends on your preferences, shooting experience, and the specific task you have been given.

Such optional items include a laptop with separate SSD drives for photos. If you are going on a long shoot (I once had a job that lasted a month and a half, photographing facades in another city), you will need to store and convert your photos from raw to jpeg so that they take up less space on your drives.

Of course, if you have a good internet connection, you can immediately send all your photos to the cloud, but this is not always the case, so it is better to have a good amount of memory on your SSD drives. This way, you can spend the necessary time shooting and then relax before the next day.

Scouting Before Shooting

Now that all the equipment has been gathered, it is time to consider the items that need to be scanned. It is best to make it a rule to scout the area before each shoot. In the case of street objects, surfaces for materials, or small structures, you first need to walk around and find them all.

Some customers require separate confirmation for each item, so you simply take a photo of all the items you find on your phone and then send them to your customer for verification. Even if this is not required, it is still better to find all the objects first and plan your scanning route.

This way, you will have a clear understanding of how many scans you will need to make, allowing you to better plan your time, and you won't have to walk around frantically searching for objects with all your equipment on your back after each scan, as sometimes the objects you need are located in completely different places.

Tip: To simplify your reconnaissance on foot, you can search for objects by looking for them on Google Maps in street view mode. This can save time, but it doesn't always help, as the images there may be old and not reflect reality. For example, the facade you need may have been closed for renovation, and certain ruins and abandoned buildings may have already been demolished, even though they are still on the maps. Use this to help with your search, but not as a complete replacement for walking.

In the case of a large complex of buildings or ruins, you may need to walk around them with your senior or coordinate everything with him remotely (unless you are the senior yourself) to determine the exact purpose of the shoot, how to divide the objects and what kind of content you want to get here: materials, props, landscape, buildings, foliage, etc.

Tip: To photograph facades, download an app to your phone that allows you to track the movement of the sun. This way, you will know when the desired part of the facade will be in the shade, which is ideal for proper scanning, and you will also understand at what time of day there will be enough light for shooting without increasing the ISO and exposure.

Consider this time period as your main working time, because after that, the scan simply won't work, and if you didn't manage to shoot something, you'll have to wait until the next day. The weather itself can also have a negative effect, so keep an eye on that as well. Plan ahead!

This practice will allow you to work in the right workflow, not waste time, and closely interact with your studio, doing only the necessary work without unnecessary stress. A well-designed plan will also help you choose the right equipment, because you obviously cannot take all the equipment you might need for every situation with you.

It's just not convenient, so optimize your work. It may seem like a waste of time, but when you take on a huge order for hundreds of scans, without the right approach and process structure, you won't be able to get everything done on time and without unnecessary rework, because reshooting everything would simply be financially unprofitable.

Let's Go Shooting

After scouting, you can safely go on a photo hunt. Be sure to bring water and something high in calories. There isn't actually that much time for shooting (it depends on the length of daylight hours, of course), so you won't have time for long breaks for lunch in a cafe, and if you're shooting in the forest, there won't be any cafes there. Quick snacks are our everything.

Once you've reached your destination, start shooting! 

For objects, the process is no different from home scanning. So, once again, I recommend reading my previous article to learn more about this.

For surface materials, find the area you like and mark it with two tape measures vertically and horizontally (the length of the tape measures depends on the required size of the material). Also, place a color checker next to the edge of the material so that it is included in the final photos.

Shooting small buildings and structures is no different from shooting objects, except for the much larger number of photos and shooting without a flash. It would be great if you are lucky with cloudy weather or if the part of the facade you need is in the shade.

For multi-story buildings or natural rocks, only drone photography is used. I haven't had this kind of experience yet, but in fact, it's no different from regular photography. The rules are the same, it's just much more difficult to shoot from a drone, and the subject is thousands of times larger than a regular apple.

Tip: When photographing any objects, facades, or materials, try to shoot them in the shade, even if the weather outside is clear. Objects can be moved into the shade of a building or tree, facades will definitely be in the shade at certain times of the day, and it is best to shoot materials in the morning or evening.

When using a flash, you don't need a lot of street light, just enough to see what you are shooting. The more natural light falls on the material or object, the more light and shadow will appear on it, and the color will change, which is naturally bad, because we need to get fully cross-polarized photos.

During my last scan, which I did in my grandmother's garden, I had to gather all the objects in the greenhouse to protect myself and the objects from the snow and cold. This allowed me to shoot even in winter, although I do not recommend shooting in such conditions.

The equipment is not designed for severe frosts. In my case, it was minus one degree Celsius. Starting at around minus five, camera and other equipment manufacturers no longer recommend shooting, unless your camera is not a hiking camera, which has a much higher operating temperature than consumer cameras.

After a great shoot, you can head home to relax and process your photos. Remembering my trip to another city to scan facades, after shooting, I went to dinner at a cafe, which allowed me to try the local cuisine. Combine work and travel. When you have the chance to travel the world for scanning purposes, don't deny yourself the pleasure and set aside at least a little time to explore local attractions, cuisine, and meet people. As far as I'm concerned, it's the perfect plan!

Conclusion

Scanning outdoors is definitely more difficult than scanning at home. Your travel and communication skills will come in handy here, and of course, it will test your endurance. You also need to be well prepared and have experience in scanning so that you can complete orders efficiently and on time. But no matter how difficult it may be, it is very interesting and inspiring.

For me personally, 3D scanning is a dream job, because I don't sit in one place, but travel and learn about the world around me. I think modern scanners are pioneers. They find unique and beautiful things, which they then present to the entire gaming and film industry as proof that even without science fiction, people and nature together can create something unimaginably beautiful right here and now.

Good luck with your new scans and other projects, and may your work bring you as much pleasure as it does me. Thank you for reading the article, and see you soon!

Alexey Gorinov, 3D Scan Artist