Since the dawn of time, artists have been trying to replicate the world around us. These days, 3D modelling and printing may be the closest way yet to do this.
A 3D model is exactly that, a model with three dimensions. When you create 3D models, you allow viewers to see height, width, and depth. The process of turning a series of images into a 3D model is called photogrammetry ut you still need to make it.
In this article, we show you how to approach, photograph, and create 3D models from photos.
What You Need to Make a 3D Model From Photos
To make 3D models from photos you will need a camera, software, and a 3D printer.
You will also need a wide-angle lens without huge amounts of distortion. For example, a 24-70mm would be perfect.
You will also need a sturdy tripod. A good tripod allows you to shoot from head height when fully extended.
You have to use software to create a 3D model from photos.
For 3D modelling, we will use the Agisoft Photoscan.
Two alternatives to Agisoft Photoscan are:
- Regard3D is a structure-from-motion program, creating a 3D model from a series of photographs.
- VisualSfM is another GUI application, resulting in 3D reconstructions using a series of images.
Once you have your 3D model, you want to bring it to life through 3D printing. If you do not own a 3D printer yourself, there are websites specified for this, such as i.materialise.com. These sites allow you to upload your 3D model while choosing the size and the material.
Step 1. Adjust Your Settings
For my example, I tried to capture the Harry Hill Bandholtz statue in Budapest. It was small enough to capture in less than 100 images and I could move around it 360°.
For the camera settings, the lowest ISO possible will provide the best quality image.
Lastly, these two above settings give you the shutter speed value.
I recommend using Manual mode. This lets you change any values you want without them affecting other settings.
Here are the settings that I used for my example picture.
Step 2. Choose Your Subject
Choose your subject carefully. 3D photographing a huge building or monument could cause many issues.
By choosing something too big, you risk not fitting the entire subject in your frame. You may also find that you cannot move around it easily. Large structures also need more and more images to create 3D models.
My advice is to location scout first. Go out with your camera, and consider leaving your tripod behind. Find a subject and take some reference shots.
Step 3. Take Your Images
To make a 3D model from photos, you need to think about panorama imaging.
Panoramas are created by photographing a scene from many camera perspectives without actually moving. You take a picture, move the camera along the same axis and photograph again. You repeat this process until you have captured the entire scene. It could cover a 360° field of view.
When you stitch these images together, you get one image showing the entire scene. You need an overlap of around 80%. Each new image you shoot needs to show 20% more of the scene than the last image. It allows the 3D software to match the images correctly.
This is why you should shoot in portrait orientation. This allows you to get the height of the subject in its entirety.
For each, you need to take a mini-panorama. This will give you the length of the subject. It will also ensure the overlap that you need to create a 3D model. You will have to move the camera, take three images and move the camera again.
The three images will follow a simple process. The first will have the subject in the middle. In the second, the subject will rest on the left rule-of-thirds intersection, and the third will rest on the right intersection.
Using the rule-of-thirds grid on the camera’s Live View, you can line everything up. Use the on-camera spirit level to ensure it is level.
Change your location by taking two medium steps from the last location. Repeat the three steps above the entire way around the statue. In each position, take three images.
Below is a drawing about my process, showing how many images I took and from what angle. I took a total of 132 images from 44 different positions, covering the full 360° view of the statue.
Step 4 – Install the Software
Go to the Agisoft Photoscan website and download, install, and run its 3D software.
Step 5 – Add and Align Your Images
Click on Workflow > Add Photos. Locate the folder where your Jpegs are stored. Next, select every image in the left-hand browser window. You can do this with Ctrl/Cmd + A.
Go back to Workflow > Align Photos. Set the accuracy to Highest and Generic Preselection to Disabled. Under Advanced, set the Key point limit to 100,000 and Tie point limit to 40,000.
Press Ok. This process might take over an hour, depending on computer speed and the number of images.
I had a problem with the camera allocation that Agisoft Photoscan uses as default.
When I first looked at the model, I was disappointed the statue was not as sharp and as ‘full’ as I had hoped. The trees and surrounding objects appeared in the shot.
This partly came from the 3D software reading the wrong placement of between 6-8 camera angles.
I tried to move these independently but instead chose to rename the files to something more coherent. The file names had the original names given by the camera.
After changing the file names and recreating the 3D model, the program placed the cameras correctly. You can see the difference in the image below.
One way is to try aligning the photos again. Add the photos, and then go to Workflow > Align Photos.
In the dialogue box under Pair Preselection, change it from Disabled to Generic. This way, the 3D software spends more time thinking about your camera placements and where your images overlap.
The reasons to use 3D Modelling range from creating special memories of travels to creating a 3D object from a photographed subject. Professionally, if you are an architectural photographer, architect, or work in similar fields, there are benefits in creating a perfect rendition of an existing object.
That said, creating a 3D model from photos is a time-consuming process. You need to have the correct camera setup, tripod, subject, and software to achieve your goal.
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