Render Methods

A breakfast room lit only by daylight through the window, rendered with Global Illumination. Apart from the patch of sunlight, every surface is lit by light that bounced off the floor, the walls and the ceiling.

The render method decides how Rayscaper computes the image. Global Illumination renders the photorealistic image. The diagnostic methods each show a single property of the scene, such as its colors or surface directions. Use them to check a model, or as extra layers to edit the render in an image editor (this is called compositing).

Choose the method with the Render Method dropdown in the Render section of the Scene Editor. Its settings appear below it.

Render Method	Use it for
Global Illumination (GI)	Photorealistic renders, from quick drafts to final images. The default.
Albedo, Ambient Occlusion (AO), Geometric Normals, Shading Normals, Texture Coordinates, World Coordinates, Material ID, Object ID	The diagnostic methods: one property of the scene each.

The Render section of the Scene Editor.

Video

Render methods and samples picks the render method for a room lit by one window. It shows Global Illumination with the Quality presets from Draft to Final, and what samples per pixel do to the grain. It also shows how AI Denoise cleans a few hundred samples, and the diagnostic methods Albedo and Ambient Occlusion. To follow along, download its scene, rayscaper-render-methods.skp (8.8 MB): a breakfast room lit by a garden HDRI through its window. It works with the free version of Rayscaper.

Quality

With Global Illumination, the Quality dropdown is the main setting. It sets the samples per pixel and how often light may bounce, through glass, off mirrors and through see-through surfaces like leaves:

Quality	Samples	Use it for
Draft	64	Checking the lighting and the composition.
Preview	256	A closer look before the final render.
Final	1024	Most final renders. The default.
High	4096	Interiors with a lot of bounced light, and scenes where glass, mirrors or dense foliage render black.

Choosing a quality preset replaces the samples and all five Advanced settings. After you change Samples per Pixel or an Advanced setting, the list shows the preset as modified, for example Final (modified). Save your values with Save as New Preset… or the save button next to the list, and they appear under My Presets in every model, or choose Revert to to go back. Use for New Models makes new models start with a quality of your choice. The list works like the presets of Post Processing.

Glass, mirrors or leaves render black?

Light that passes through several panes of glass, bounces between mirrors or crosses many leaves can run out of bounces. Choose High: it allows more bounces of every kind. If it takes too long, lower the Samples per Pixel afterwards, the extra bounces stay.

Samples per Pixel

Rayscaper renders by tracing many random light paths through every pixel. Each path is one sample. A few samples give a grainy image, and every extra sample averages the grain away. Samples per Pixel sets when the render is finished, from 1 to 32,000. The default is 1024.

16 samples

16 samples: the shapes and the light are there, the grain hides the details.

64 samples

64 samples: good enough to judge the lighting and the composition.

256 samples

256 samples: only fine grain is left, in the darker areas.

1024 samples

1024 samples: almost clean.

These renders have the AI denoiser turned off, to show the grain itself.

Rooms lit by daylight through a window, like this one, need more samples than outdoor scenes: most of their light arrives after several bounces, and every bounce adds randomness. Brightly lit exteriors are often clean after a few hundred samples.

Tip

AI Denoise, on for a new model, removes most of the grain, so a few hundred samples often look as clean as thousands. Toggle it with the Denoise button (the sparkle icon) on the toolbar, or in the Post Processing section. To find the right number for a scene, make quick test renders at a lower resolution first.

Advanced

With Global Illumination selected, expand Advanced below Samples per Pixel to adjust how light travels through the scene. Start with a quality preset, then change only the settings your scene needs. Higher bounce limits can increase render time; more samples reduce grain but do not restore light paths cut short by a bounce limit.

Setting	Range	What it controls
Diffuse Bounces	0–16	Light bouncing off matte surfaces, such as walls and ceilings. Increase it when an interior needs more indirect light. At 0, diffuse indirect bounces are removed.
Reflection Bounces	0–16	Glossy and mirror reflections. Increase it if repeated reflections, such as two mirrors facing each other, turn black.
Transmission Bounces	0–16	Light refracting through glass and water. Entering and leaving a solid pane each use a bounce, so several panes need a higher limit.
Transparent Layers	0–128	Surfaces a ray passes through using opacity, such as leaf cutouts or partially transparent SketchUp materials. Increase it if overlapping layers turn black. This limit is separate from refractive transmission through glass and water.
Highlight Clamp	0–1,000,000	Limits very bright samples to reduce isolated bright specks, or fireflies. Lower positive values clamp more strongly and can darken highlights and reflections. 0 disables clamping.

The quality presets set these starting values:

Quality	Diffuse Bounces	Reflection Bounces	Transmission Bounces	Transparent Layers	Highlight Clamp
Draft	2	2	4	64	5
Preview	4	4	6	64	10
Final	5	5	7	64	10
High	8	8	12	128	20

For example, if several glass panes render dark at Final quality, raise Transmission Bounces while keeping the other values. For a hedge made from overlapping leaf cutouts, raise Transparent Layers instead. If a few bright specks remain, try a lower positive Highlight Clamp, checking that wanted highlights still look right.

These settings are saved with the model. Collapsing Advanced keeps your values; Reset to Defaults restores Global Illumination at Final quality, including these settings.

Diagnostic Methods

These methods each show one property of the scene instead of a lit image. Use them to check a model. Or save them as extra layers and combine them with the render in Photoshop, After Effects or similar software.

Albedo

The base color of every surface, without any lighting or shading. Handy to check materials and textures, and as a color layer in compositing.

The albedo pass. The herringbone parquet, the tablecloth and the rug show their real colors, without light or shadow.

Ambient Occlusion

Shows how open every point is: white where nothing nearby blocks the view of the surroundings, darker in corners, gaps and under objects. Multiply it over a render in post-production to add depth to contact areas.

AO Distance sets how far to look for nearby surfaces, from 0.001 to 100 m. The default is 10 m.

0.1 m

Only contact shadows and tight gaps, like under the plates and along the skirting boards.

0.5 m

Soft shading under the table and the sideboard.

2 m

Broad shading in the corners of the room.

Geometric Normals

The direction every face points in, as a color: X (red), Y (green) and Z (blue). This uses the actual faces of the model, without smoothing or normal maps, so it shows the real geometry. Negative directions can’t be shown as a color, so faces that point along -X, -Y or -Z, like the back wall here, render black. The floor is one even color, because its boards only exist in the normal map.

Shading Normals

Like geometric normals, but after smoothing and normal maps, so it shows the surface direction that the lighting actually uses. Compare it with the geometric normals to check that normal maps and smoothing work as expected: here the normal map of the floor shows up as a pattern of boards.

Texture Coordinates

The texture coordinates (UVs) of every surface as a color: U is red, V is green. Use it to check that textures are placed, scaled and oriented as intended.

World Coordinates

The position of every surface in the scene as a color: X (red), Y (green) and Z (blue), in meters. Values above 1 show as full color and negative values as black, so save it as EXR (needs a license) to keep the real positions.

Material ID

Every material in a flat color of its own, on a black background, or a transparent one when the environment has a transparent background. Use it as a mask: select a material in Photoshop or another image editor with the magic wand on this pass, then edit that selection on the render.

The color of a material follows from its name, so a material keeps its color in every render of the model, also after you open the model again: masks of several views or of a later render use the same colors. Renaming a material changes its color. Glass is opaque in this pass, so a glass pane gets its own color. Leaves and other materials cut out with an opacity texture show what is behind them. (The window of this example scene has no glass, so the background shows through it in black.)

To save it next to the render of every scene, check Material ID under Passes in Render Scenes.

Object ID

Like Material ID, but a flat color per object: every group or component in the model, with everything inside it, whatever its materials. Select a sofa or a car with the magic wand, while Material ID selects its fabric or its paint. Two copies of a component get two colors. The faces outside groups and components share one color, and so do the instances of a scatter.

An object keeps its color when you move or edit it and after you open the model again. Glass and opacity textures work as in Material ID.

Render Scenes saves it as a pass too, with Object ID under Passes.

Reset to Defaults

The Reset to Defaults button at the bottom of the section resets the render method and its settings to those of a new model: Global Illumination at Final quality, or at the quality you use for new models.

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Credits

The example scene on this page is built from CC0 models, textures and HDRIs from Poly Haven.