LichtFeld Studio v0.5.4.2 adds optional POPSpa post training sparsification to the open source gaussian splatting trainer, inside a release billed as a security update.
POPSpa runs after training finishes and removes splats the result does not need. Opacity ADMM stays the unchanged default, and POPSpa is opt in from the Training panel, the command line, JSON and Python. The implementation is native C++ and CUDA on both the FastGS backend and the bundled gsplat/GUT backend. Contributor lyehe describes it as an independent implementation of the unofficial POPSpa profile in OpsiClear's KissGsVanilla repository, not the original authors' unreleased encoder. Checkpoints move to format v4, which needs the updated app, while v1 to v3 still load.
v0.5.4.1 added training inside a live crop box in the GUI. The new --cropbox x0,y0,z0,x1,y1,z1 flag gives headless training the same region of interest. Setting --cropbox-loss-weight 0 ignores every pixel whose ray misses the box, and the box is saved with the project as an ordinary crop box node the GUI can edit.
LichtFeld Studio's MRNF strategy fills its splat cap early in training, after which its error guided growth has no budget left. A new growth_exchange refinement option from first time contributor hellguz, off by default at 0, frees a share of the least important splats at each refine once the cap is reached, and normal growth places them where the error is. On the FastGS backend, a splat is freed only when it ranks low on both coverage and peak blend weight, which protects both large soft splats and small opaque ones. The gsplat/GUT, Vulkan and Metal rasterizers rank by coverage alone. The pull request reports higher PSNR on five of six Mip-NeRF 360 and Tanks and Temples scenes with growth_exchange at 0.02, with training taking 5 to 10% longer on a power-capped RTX 5070 Laptop GPU.
The security fix targets eight eMudhra intermediate certificate authorities whose private keys, according to the release notes, can be recovered from their certificates. LichtFeld Studio's downloads and plugin installs now reject chains through those CAs, checked against their public keys as Go and Node do, and the bundled uv moves to 0.13.5. The release notes warn that an intercepted plugin install could run arbitrary code. Dependency bumps include OpenSSL 3.6.5, curl 8.23.0 and FFmpeg 8.1.2.
Interface changes add selection outlines for splat objects, vertical category tabs in the right sidebar, a double click on a setting's label to restore its default, configurable arrow key repeat for camera images, and a prompt to enable undistortion or GUT when distorted cameras are detected. Fixes cover a shared memory race in the layer norm kernel, video frame extraction, scaled training intervals that rounded to zero steps, Windows builds, and reopening projects with training checkpoints.
LichtFeld Studio v0.5.4.2 is available now on GitHub under the GPL-3.0 license.
