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Capture/Photogrammetry

As the lines between real and virtual worlds continue to blur, ZBrush for iPad pioneers the integration of photogrammetry, which is the use of overlapping images taken at different angles to create accurate 2D and 3D models that digitally reconstruct the original physical source. Especially for users who might struggle with modeling from scratch, the photogrammetry features in ZBrush for iPad offer a phenomenal leap in creative convenience and power.

Getting Started

LiDAR-driven photogrammetry with an iPad has been a wondrous innovation in the 2020s. In practice, some scans will benefit from post-capture refinement. You can lighten the editing load by exercising a handful of photogrammetry best practices, such as:

• Use diffuse, even light, preferably natural or from softboxes.


• Walk slowly while scanning with LiDAR.


• Keep an eye on ZBrush's on-screen distance warnings saying you are too close/far from your object.


• Expect shiny or translucent objects to be challenging. Mid-tone, matte objects, especially with some speckling, tend to yield the cleanest results. You might consider applying some talcum or similar powder to achieve a more matte surface, although this would likely impact the subject's texture.

From the ZBrush for iPad home screen, tap the Capture button near the UI's bottom-left corner, just below the New Sculpt button. This launches the camera routine. Note the four L-shaped cropping guides that are at equidistant corners from the center spot. Make sure your subject is within these guides and adhere to any suggestions the app makes around lighting, distance to subject, etc. When you're ready tap the Continue button in the top-right corner.

On the next screen, observe the ground plane box placed around your subject. Drag the thick, glowing white handles around the sides and top of the box to rotate the box and adjust its dimensions. You want the box to fit fairly closely around your subject without clipping it.

Be sure to change your position and elevation to make sure you've got the ground plane box just how you want it.

When you're satisfied with the ground plane box, tap Start Capture.

From here, ZBrush begins capturing and compiling images. Again, you'll want to watch any direction messages (e.g., move slowly, get closer, etc.) in the UI. You'll also observe ZBrush begin to assemble a sparse point cloud (the floating dots you see building up in real time) to the right of your subject. This shows you what ZBrush has already constructed. The point cloud can reveal areas missing from your model capture. Similarly, the coverage ring is a series of white lines that forms around the point cloud's perimeter. Each segment in the ring turns white when ZBrush decides it has enough overlapping images from that area and angle to reliably reconstruct that part of the mesh.

In the top-right corner of your capture UI, you have the Auto and Next buttons. ZBrush defaults to capturing the model in Auto mode, which is why the button normally shows as enabled. If you tap the button to disable it, ZBrush goes into a manual capture mode. You can use the coverage ring to help guide you here, just as you do in Auto mode. Manual mode can be helpful on occasions when you want to fine tune camera angles. Usually, though, Auto is convenient and works well for most capture tasks. Alternatively, if you're content with the captures you have and want to cut your photo collection short, simply click Next to proceed.

When your coverage ring is full, ZBrush pops up an alert informing you that your pass is complete.

As the message says, ZBrush prefers three scan passes. Use these to cover the model at different angles. ZBrush also gives you the option of flipping your subject to reveal a different face. Depending on the properties of your subject and/or the needs of your project, this may or may not be advisable. For example, flipping is best for solid objects. You wouldn't want to flip a piece of cloth, because it would deform during movement.

Once you complete three passes, ZBrush analyzes all your scanned images into a final model. Model generation happens on-device, so your hardware's perfomance will affect the generation time, as will the number of images collected. The mesh you see below is based on 79 images captured.

Check out the results. Not bad for a few minutes of work, right?

Use the Save icon at the top-left corner of the UI to save your model and give it a name. Once you do, it will appear in the Recent Sculpts gallery in ZBrush's home screen. And as with other 3D models, you can export captured models or even insert them into an already-sculpted model to test your design!