The Intel RealSense D455, D415, and D435 (as well as D435i) sensors are a great choice for scanning outdoors and/or in sunlight.
However, as with all sensors, they have both advantages and limitations. Following best practices is highly recommended for the best results.
Pros:
+ Can scan outdoors, even in full sunlight
+ Very inexpensive
+ Good build quality and very sturdy
+ Great support by Intel including driver updates, FW updates, re-calibration SW, etc..
+ Works on Windows and Andoid OS
Cons:
- Overall noise level (and hence reconstruction quality) is relatively high, especially for the D435 and D435i.
- The usable range is well below 3 meters, making scanning larger scenes or objects difficult.
- Sometimes has difficulty picking up small geometric details.
Best practices:
* When scanning outdoors, having bright daylight often improves the data quality. This is because the D415's and D435's stereo cameras are able to perceive details better when the scene is brightly lit. The pattern projector does not play a role in this scenario as daylight eliminates visibility of the IR projected pattern to the stereo cameras. This is why you may still have trouble scanning completely textureless objects.
* When scanning indoors, best results are obtained in when daylight is absent and rooms are illuminated by artificial light. This is because daylight eliminates visibility of the IR projected pattern to the stereo cameras. If daylight is absent the IR pattern helps the stereo sensors perceive geometry accurately.
* When scanning parts of a scene or object that are mostly uni-color with no texture, try to put something textured on. AprilTags are often a good choice, but make sure you don't print and use a tag ID twice in one scan. This will help the tracking and stitching.
* Try to move further away when scanning so you get more in the field of view of the camera. This will help the tracking and stitching and reduce your overall scene size and drift. However, this is a delicate balance as the noise level increases with distance. Move closer to the surface only when you need more resolution / detail on a particular spot.