Fixing Flat or Missing 3D Textures After Installing Optimum Realism

Confirm the pack is actually loaded

Open Options > Resource Packs and check that Optimum Realism sits above the default pack and is not greyed out. If it shows as incompatible, your Minecraft version does not match the pack's supported range — you need a build of the pack made for your version. A pack that loads but shows vanilla textures usually means the pack is selected but not moved to the 'Selected' column.

Check the shader, not the pack

POM and PBR are shader features. If the pack is loaded and textures still look flat, the problem is almost always the shader. Switch to a known LabPBR-supporting shader, then re-enable Parallax and Normal Map in its options. Some shaders default these off even when they support them.

Rule out conflicts

Other resource packs that touch the same blocks (leaf packs, connected textures packs, GUI packs) can override Optimum Realism's normal and specular maps. Remove all other packs temporarily and test with only Optimum Realism plus your shader. If depth appears, re-add packs one at a time and keep the offender below Optimum Realism in the list. Also disable any 'Connected Textures' or 'Emissive' toggles in the shader that might be fighting the parallax pass.