A lot of the 3D Gaussian footage that's been posted has just been a screen recording of the SIBR viewer. As amazing as the processed files look, creating and rendering out a camera path has not been easy. That just changed, with Github user, yzslab, posting a fork of nerfstudio that allows you to view your 3D Gaussian Splats within nerfstudio's viewer.

From the creator on installation:

You need to install the nerfstudio denpendices first, then plyfile==0.8.1, submodules/diff-gaussian-rasterization and submodules/simple-knn. By running python nerfstudio/scripts/gaussian_splatting/run_viewer.py --model-path GAUSSIAN_TRAINING_OUTPUT_DIR, you can use the web-based viewer of nerfstudio to view your scene.

Please note that currently training is not available, but to be able to utilize the nerfstudio camera path and render pipeline is a significant improvement over the SIBR viewer.