Lumion Output Post-Production
A Lumion render is a starting point. Post-production is what takes it from technically correct to visually compelling.
Why post-production matters
Lumion outputs are good renders. They are not, by themselves, polished presentation images. The atmospheric qualities that Lumion handles well — lighting, material rendering, entourage density — often need refinement at the image level: color grading for presentation consistency, shadow and contrast adjustment, sky replacement for a more dramatic or precise atmosphere, people replacement for photographic realism, and cleanup of rendering artifacts and edge conditions. Post-production in Photoshop is the professional standard for all rendered images regardless of their source software.
Lumion output passes
| Pass | What it contains | How it's used in Photoshop |
|---|---|---|
| Main render (JPEG or PNG) | The primary rendered image — all materials, entourage, lighting, and effects composited into a single image | The base layer. Everything else is added above it. |
| Shadow pass | A separate render showing only the shadow information — dark where shadows fall, white/transparent where they don't | Place above the main render, set blend mode to Multiply at reduced opacity. Allows independent control of shadow depth and softness without re-rendering. Can be selectively masked to remove or intensify shadows in specific areas. |
| Material ID pass | A flat-color map where each material is rendered as a distinct solid color, with no lighting or shadow | Used as a selection tool — use Select → Color Range to select all pixels of a specific material color, then activate the main render layer and use the selection as a mask for targeted adjustments or replacements (including people replacement). |
| Alpha map (sky replacement) | A mask where the sky area is white and all solid scene elements are black (or vice versa) | Load as a selection, invert if needed, and use to mask a sky replacement layer above the main render. Produces a clean sky swap without manual selection. |
Lumion people replacement workflow
Lumion Education's human figures are stylized and read as rendered rather than photographic. For presentation images where figure realism matters:
- Open the Material ID pass and use Select → Color Range to select the color representing the figures (if they are a distinct material ID color in the Lumion file)
- Alternatively, manually select each figure using the Polygonal Lasso or Quick Selection and Refine Edge (Card 09–10)
- Use the selection as a mask on the main render to hide the Lumion figures
- Place photo-extracted replacement figures (from the entourage library) in the same positions — match scale to the Lumion scene geometry, match lighting direction to the Lumion sun
- Clone Stamp around the edges where the Lumion figure was removed to clean up any residual artifacts
- Apply a clipped color grading adjustment layer to each replacement figure to match the scene color temperature
General color grading for Lumion outputs
Apply the grading sequence from Card 16. For Lumion-specific corrections:
- Lumion renders often read as slightly oversaturated — reduce Vibrance slightly in Camera Raw
- Lumion shadows are sometimes flat or have a slight warm cast — use the shadow pass with Multiply blending to deepen them, and a cool Color Balance adjustment in the shadow range
- Vegetation in Lumion Education can read as overly uniform green — use Hue/Saturation to introduce slight variation: some areas slightly yellow-green, some blue-green
- The overall scene should match the color temperature of your other images in the series — use Match Color (Card 16) to harmonize
What breaks
Not saving the Lumion passes at the same resolution as the main render — the shadow pass and alpha map must be pixel-identical to the main render to align correctly. Verify dimensions match before compositing.
Shadow pass at 100% opacity — the Lumion shadow pass at full opacity will produce heavy, pure black shadows that look nothing like real outdoor shadow conditions. Start at 40–60% opacity and reduce from there based on the desired shadow depth.