Fly-Through: 3D Camera

OsiriX and Horos Course · 3D Reconstruction

In this lesson I show how to do a fly-through in OsiriX, a 3D reconstruction in which you create a path (trajectory) and the camera travels along it, generating an excellent video for presentations. The example is an interesting case of lower-limb leiomyosarcoma originating in the muscular layer of the vein (venous leiomyosarcoma). In the study there are multiple lesions along the path, and I want to guide the viewer through the main areas — including regions in the middle of the path and a relationship/continuity close to the posterior tibial artery. 1) Opening Fly-through and adjusting the view I locate the Fly-through icon and open the tool I select GPU mode (using the graphics card) I adjust brightness and contrast to visualize: a bit of the muscle and the venous lesions with better definition 2) Creating the “steps” (camera points) With the fly-through window open, I start creating the key images (keyframes): I set the initial image as the first step I rotate the volume a little and adjust the zoom to focus on the first lesion → I add the 2nd step I create a 3rd step to highlight another lesion At this point, I adjust brightness/contrast to improve the view I move further down and rotate a bit to show the intermediate lesions → more steps I create a final image, for a total of 6 images/points along the path These points work as “landmarks” the camera will pass through in the video. 3) Generating the video (frames and spline) Once the steps are defined: I choose 300 frames I enable Spline, so the camera makes a smoother transition (a more natural curve) I click to compute the images Preview (Play) The Play button lets you see how the movement will look Not necessarily in real time, because it is computing frame by frame 4) Exporting to video (QuickTime) I choose to export to QuickTime I select the best-quality option I save the file and OsiriX exports the fly-through, navigating the 3D according to the steps created 5) Tip on smoothness: frames per second In the video I explain: For a sense of motion, we think of ~24 frames per second 300 frames gives roughly 10 seconds of smooth video (in principle) If the result feels “slower” (with the impression of pauses), you can speed the video up a bit on playback to make it more natural