Interior render workflow in Blender: from CAD to final image

This is the workflow I use to take a SketchUp or DWG file from an architect and produce a finished interior render in Blender. It's the same pipeline I've used on residential and hospitality projects for the last three years. Nothing here is theoretical. Every step is what I do on Monday morning when a new brief lands.

I'm assuming you know Blender well enough to navigate the interface. If you don't, learn the navigation first; this guide won't help.

Step 1: Get clean geometry in

The architect sends you a SketchUp file. You import it. The first thing you do is throw away half of what comes in.

Architectural source files are full of hidden geometry: layers turned off, doors swinging in plan, dimension annotations as 3D extrusions, exploded blocks. Cycles will render all of it.

What I do, in order:

1. Import SKP through Blender's native importer (or via FBX if the file is large).
2. Hide every collection that isn't the room I'm rendering. Keep walls, floors, ceiling, and the structural frame.
3. Recalculate normals on everything (Edit Mode → Mesh → Normals → Recalculate Outside). SketchUp normals are unreliable.
4. Apply scale. Imported geometry often arrives at 0.0254x scale (inches-to-meters issue). Apply rotation and scale on every object before doing anything else.
5. Delete any geometry below the floor or above the ceiling. Cycles bounces light off it whether you can see it or not.

This step takes 30 to 90 minutes on a normal house file. If it's taking longer, the source file is broken and you should request a rebuilt file before continuing.

Step 2: Set up your cameras

Set the cameras before you light or texture anything. The lighting decisions you'll make depend on what's in frame and what isn't.

For interior rendering I use:

• 35mm to 50mm focal length for natural-looking room shots. A 24mm wide-angle is tempting but distorts proportions in a way that looks rendered.
• Camera height at 1.4 meters (sitting eye level) for living and dining areas, 1.1 meters for cozy rooms, 1.6 meters for formal spaces.
• Two-thirds rule for the horizon line. The strongest interior compositions place the architectural horizon (where wall meets ceiling, or where countertop meets backsplash) at the upper or lower third of the frame.

Save each camera as its own object, name them clearly (cam_lounge_a, cam_lounge_b), and bind them to the timeline so you can switch with a hotkey.

Step 3: Build the lighting before you texture

Counterintuitive but important: light first, texture second.

A scene lit beautifully on grey clay reads as architectural. The same scene textured beautifully but lit poorly looks like a video game. Texture is amplification; lighting is structure.

For a daylight interior:

1. Add a Sun lamp, position it as if from the architect's actual site direction. Strength around 3 to 5, soft angle 0.5 degrees for crisp shadows or 2 degrees for soft.
2. Add an HDRI to the World shader. I use Poly Haven's "kloppenheim_06" or "venice_sunset" for warm afternoons. World strength around 1.0.
3. Add a Plane outside each window, scaled to match the window opening, with an Emission shader at strength 50 to 100 and color 4500K to 5500K. This simulates sky-and-cloud bounce that fills the room with cool ambient. Without it, your interiors will look harshly lit by the direct sun and nothing else.
4. Set Cycles film to "Filmic" with high contrast. Default sRGB clips highlights in interiors.

For a twilight interior, replace the sun with a much weaker dim source (strength 0.5), drop the HDRI to 0.2, and add interior emissive fixtures (lamps, recessed lights) at warm color temperatures (2700K to 3000K, strength 100 to 500 depending on size).

Step 4: Materials

Blender's Principled BSDF handles 95% of architectural materials. I rarely use anything else.

Wood floor (smoked oak):

• Base color: import a 4K wood texture from a free library (Poliigon, AmbientCG, or a scan you bought from RDT).
• Roughness: medium-high (0.4 to 0.6), with a roughness map if available.
• Normal: use the texture's normal map at strength 1.0.
• Add a small amount of clearcoat (0.1) for that just-waxed look on living room floors.

Plaster walls:

• Base color: a warm off-white, around RGB 0.92, 0.91, 0.88.
• Roughness: 0.85 to 0.95. Plaster is matte.
• Bump: very subtle noise procedural texture, strength 0.05. Painted plaster has microsurface that catches grazing light.

Marble counter:

• Base color: photographic texture or scan.
• Roughness: 0.05 to 0.15. Polished marble is glossy.
• Specular: 0.5 (default). Don't go higher; it overcooks.
• Subsurface: 0.05, color slightly warmer than base. Real marble has slight light penetration.

Glass:

• Base color: white.
• Roughness: 0.0 (perfectly clear) or 0.05 for slight haze.
• Transmission: 1.0.
• Ior: 1.45 for window glass.

Don't use Glass BSDF. Principled with Transmission renders cleaner and is easier to tune.

Step 5: Render settings

For a 4K interior on a 4090:

• Cycles, GPU Compute, Hybrid (CPU + GPU) if you have 32GB+ system RAM.
• Sampling: 256 to 512 samples adaptive, with denoiser ON (OpenImageDenoise, "Optix" mode).
• Light paths: 12 max bounces total, 4 diffuse, 6 glossy, 8 transmission. Defaults of 12 across the board are excessive for archviz.
• Resolution: 4K (3840 x 2160) for hero shots, 1920 x 1080 for previews.
• Output: 32-bit EXR for the master, plus a 16-bit TIFF or PNG for fast review.

A 4K interior at these settings takes 1 to 2 minutes per frame on an RTX 4090 or 5090 with the OptiX denoiser on. Iteration at 1920p is under a minute. The render itself is no longer a meaningful part of the timeline; the lighting and material work that comes before it is.

Step 6: Post-production

Bring the render into Photoshop or DaVinci Resolve. The post-production stage takes an interior from "rendered" to "photographed."

What I do, in order:

1. Color grade. Lift the shadows slightly, add a touch of warmth in the midtones, cool the highlights. The exact curve depends on the mood, but every render gets touched.
2. Bloom. A subtle bloom on bright lights and window frames helps the eye read it as a real photograph.
3. Chromatic aberration. Tiny, like 0.5 pixels. Real lenses have it; renders without it look too clean.
4. Grain. Add film grain at 1 to 2% intensity. Critical for matching photographic output.
5. Vignette. Soft, subtle. Don't crush the corners.
6. Final crop. Reframe if needed. Often a 5% crop in tightens the composition.

I have a much longer post on color grading 3D renders in DaVinci Resolve if you want to go deeper into post.

Common mistakes I see

• Lighting from "Render Properties → World" alone. Every interior needs supplemental window-bounce planes.
• Using Glass BSDF instead of Principled with Transmission.
• Leaving samples at 4096 because you saw it in a tutorial. With modern denoisers, 256 to 512 is enough for most archviz scenes.
• Skipping post entirely. The render is 80% of the job. Post is the last 20%, and it's the difference between amateur and professional output.
• Importing SketchUp files without recalculating normals. You'll get black patches in the final render and you won't know why.

Bottom line

The Blender interior workflow in 2026 is mature enough for paid client work. The pipeline above produces output that ships to architects and developers without complaint. The render engine is one piece. The lighting and post are the bigger pieces.

For the equivalent workflow in 3ds Max plus V-Ray, see realistic kitchen rendering with 3ds Max and V-Ray. For why I use multiple engines instead of just one, see Blender vs V-Ray vs Corona for archviz.