Remember that DIALux is a shell; you still need to download luminaire plugins (from brands like Philips, Zumtobel, or Osram) or use ULD/IES/LDT files to get accurate data.
Official support for DIALux 4 ended several years ago, so links to specific versions like 4.3 are primarily found on software archiving sites: dialux 43 download link
DIALux is a free, professional-grade 3D design program used to calculate and visualize lighting effects for buildings, individual rooms, and outdoor spaces. Standards Compliance: Remember that DIALux is a shell; you still
Step 6 — Legal and security caution
: Provides a direct link to the setup_d_41301.zip file. Remember that DIALux is a shell