Chart renderer

Overview

The Chart renderer displays scene chart texturing and output density.

Chart renderer modes

Ray Origins mode

If this mode is not available, set the computeRayOriginOutput parameter to true.

Enabling this mode increases the memory footprint of the light transport phase of the precompute. In some cases, you may get an 'out of memory' error, especially when using 32 bit versions.

The Ray Origins rendering mode displays debugging information for the light transport phase of the precompute. When you select this mode, the Ray Origins tab is displayed.

This mode renders the selected system with colour coded pixels to highlight issues with ray origins. Select Show Legend to display the meaning of the colour codes. Pixels in the selected system that have no issues are rendered with a dark random texture. Other systems in the scene are rendered with a greyscale random texture.

When you select Render origin data, additional options become available:

System	Displays currently selected system ID. The slider below selects the system.
Filter on selected system	Renders only the selected system.
Show Targets	Shows only the meshes which contribute to the radiosity computation.
Render undersampled pixels	Renders colour-coded texture overlay on the selected system highlighting pixels with ray origin issues.
Render origin data	Renders colour-coded origin points and/or backface rays.
Render backface rays	Renders yellow lines showing ray segment that caused origins to be rejected.
Render valid origins	Renders points for all valid origins.
Render invalid origins	Renders points for all rejected origins.
Filter on selected pixel	Renders only origin data for a single selected pixel. A pixel is selected by right-clicking the pixel and clicking Select Bucket and Pixel.
Render backfaces	Renders backfaces in orange.
Show legend	Displays an explanation of the colour codes.

Chart Texture mode

This is the default mode. The Chart Texture mode displays the lightmap UVs generated by the precompute. This mode is very useful for debugging mesh projection issues.

Each chart is displayed in a unique colour, with a checkerboard grid displaying output density.

To display a specific chart, right-click on a chart and select Select Chart. All other charts are greyed out:

-- select chart -->

To reset the selection, right click and select Clear Selection.

You can use the Chart Texture mode to examine mesh projection. Right-click and select Toggle show targets while in Chart Texture mode to check how well the charts on the detail mesh have projected onto charts on the target mesh.

The example below shows the Arches asset in Chart Texture mode, viewed in the Filter tab with Show Target Geometry first turned off and then turned on:

Right-click again and select Select chart to check in detail how the detail meshes project onto the target mesh:

Chart and UV Generation

The Chart and UV Generation mode shows in colours the charts Enlighten sees from any mesh loaded into GeoRadiosity. It does not show the same charts that were used during the precompute (use the Chart texture mode for this), but allows you to see how changing the chart identification parameters will affect the charting. The options to control the charting can be located by right-clicking on any geometry in the scene.

When the Chart and UV Generation mode is selected, a separate Chart and UV Generation tab is available with further options.

Geometry UV processing behaviour

Chart detection	Detect input geometry charts using the vertex method.
Chart detection (edge method)	Detect input geometry charts using the edge method.
Pack geometry	Pack input geometries (will also generate lightmap UVs).
Process everything	Process the whole scene.
Clear all results	Clear cached results.
Process only detail meshes	Process only detail meshes (target meshes will be ignored).
Process only LODs	Process only detail meshes of a given LOD (target meshes will be ignored).
Override output pixel size	Enable pixel size override.

Display options

Show aggregate stats	Show aggregate stats for packed geometries.
Override Auto UVs behaviour	Use the specified automatic UV simplification mode specified below.
Override merging parameters	Use the chart merging parameters specified below.
Max plane distance	Max distance between input charts for them to be considered for merging.
Max normal deviations (initial/general)	Max angular (degrees) deviation between input charts for them to be considered candidates for projection plane creation, and max between input charts and projection plane respectively.
Overlap expansion %	Bounding box expansion when detecting which input charts overlap.
Significant area ratio	Ratio of the chart area within which normals point at more than 90 degrees from the chart principal normal to the area of the chart above which the chart is considered curved. Also a ratio of the chart area to the area of the merged group below which the chart is considered insignificant.
Num iterations	Maximum number of algorithm iterations to use to find the best projection plane.
Max fitted	Maximum number of merged groups.

Chart detection controls

Override chart detection	Enable input chart detection options override.
Remove degenerates	Remove degenerate charts.
Link identical vertices	Link together identical charts (determined by the options below).

Identical is defined by unique...

Position	Vertex positions must match for two vertices to be considered identical.
Normals	Vertex normals must match for two vertices to be considered identical.
Chart UVs	Vertex chart UVs must match for two vertices to be considered identical.
Albedo UVs	Vertex albedo UVs must match for two vertices to be considered identical.

Show edge method (parametiser) / Show vertex method (precompute)	Change the charting method to be either the edge or vertex mode.
Show without using / Show including degenerates (default)	Whether to remove topologically degenerate triangles before charting, or leave them in (the default).
Show with / without linking identical vertices	Whether to compare and link together vertices that are 'identical'. The following four comparison flags are only relevant if this option is set to 'Show with linking identical vertices', otherwise these flags are not used.
(Do not) compare positions	Whether to compare vertex positions to establish whether two vertices are identical.
(Do not) compare normals	Whether to compare vertex normals to establish whether two vertices are identical.
(Do not) compare chart UVs	Whether to compare vertex chart UVs to establish whether two vertices are identical.
(Do not) compare albedo UVs	Whether to compare vertex albedo UVs to establish whether two vertices are identical.

For further details of these options, see The lightmap UV pipeline