Material Shape Attributes

The material shape attributes control the shading, texturing and export of the shape's geometry. CityEngine supports ten texture channels with a fixed semantic.

All of these attributes can be changed using the set or setMaterial operations. You can use the print operation to output the value of a certain material attribute, eg. print(material.color.r).

Syntax

Attribute	Description
string material.name	The name of the material.
string material.shader	The shader name. Default is "CityEngineShader". Setting it to "CityEnginePBRShader" signals that the physically-based rendering attributes should be used, see below.
float material.color.{r\|g\|b}	Diffuse color (non-linear sRGB). Individual access to each color component. Default is white. More details.
string material.color.rgb	Diffuse color. Access to the complete color as hex-formatted string, eg. RED = "#ff0000". Default is "#ffffff". More details.
float material.ambient.{r\|g\|b}	Ambient color (non-linear sRGB). Individual access to each color component. Default is black.
float material.specular.{r\|g\|b}	Specular color (non-linear sRGB). Individual access to each color component. Default is black.
float material.emissive.{r\|g\|b}	Emissive color (non-linear sRGB). Individual access to each color component. Default is black.
float material.opacity	Opacity factor. 1 is fully opaque, 0 is fully transparent. Default is 1.
float material.reflectivity	Reflectivity factor. 0 is no reflection, 1 is full reflection (of the Reflection Map set in the Scene light and panorama settings). Note that reflection depends on the specular color: the default black color means no reflection!
float material.shininess	Phong specular exponent in the range [0, 128]. Default is 1.
float material.bumpValue	Controls the bump scaling factor (if material.bumpmap is set). Default is 1.
float material.metallic	Controls the metallic factor (if material.metallicmap is set). 0 is a dielectric material, 1 is a metallic material. Default is 0.
float material.roughness	Controls the roughness factor (if material.roughnessmap is set). 0 is a completely smooth material, 1 is a completely rough material. Default is 1.
bool material.doubleSided	Controls if the material is supposed to be seen from both sides of a polygon. If set to false the material is supposed to only be seen from the side the normal points to. Default is true.
string material.colormap string material.bumpmap string material.dirtmap string material.specularmap string material.opacitymap string material.normalmap string material.emissivemap string material.occlusionmap string material.roughnessmap string material.metallicmap	Texture file paths for the texture channels. More details.
float material.{colormap\|...\|metallicmap}.s{u\|v}	Per-channel texture scaling factors.
float material.{colormap\|...\|metallicmap}.t{u\|v}	Per-channel texture translation factors.
float material.{colormap\|...\|metallicmap}.rw	Per-channel texture rotation factors. The texture is rotated around the w-axis (w is the cross product of u and v).
string material.opacitymap.mode	Controls how the opacitymap is combined with the colormap. Valid values are "blend", "mask" and "opaque". Default is "blend".
float material.opacitymap.cutoff	When material.opacitymap.mode is set to "mask", the material.opacitymap.cutoff attribute specifies the cutoff threshold. If the alpha value is greater than or equal to the cutoff value then it is rendered as fully opaque, otherwise it is rendered as fully transparent. This attribute is ignored for other modes than "mask". Default is 0.5.

PBR Material Attributes

Some material attributes are designed to be exclusively used for physically-based rendering (PBR) shaders. These are:

```
material.emissivemap
```
```
material.occlusionmap
```
```
material.roughnessmap
```
```
material.metallicmap
```
```
material.emissive.{r|g|b}
```
```
material.metallic
```
```
material.roughness
```

If the shader name is set to "CityEnginePBRShader", the CityEngine viewport and encoders which support PBR materials use those attributes as well as the

```
material.color.{r|g|b}
```
```
material.colormap
```
```
material.normalmap
```
```
material.opacity
```
```
material.opacitymap
```
```
material.opacitymap.mode
```
```
material.opacitymap.cutoff
```

attributes.

Here is how the CGA material attributes correspond to the GLTF material specification, which is based on Physically-Based Rendering (PBR).

CGA material attributes	GLTF material specification
material.color.{r\|g\|b}	pbrMetallicRoughness.baseColorFactor, RGB components
material.opacity	pbrMetallicRoughness.baseColorFactor, A component
material.colormap	pbrMetallicRoughness.baseColorTexture, RGB channels
material.opacitymap	pbrMetallicRoughness.baseColorTexture, A channel
material.metallic	pbrMetallicRoughness.metallicFactor
material.roughness	pbrMetallicRoughness.roughnessFactor
material.metallicmap, B channel	pbrMetallicRoughness.metallicRoughnessTexture, B channel
material.roughnessmap, G channel	pbrMetallicRoughness.metallicRoughnessTexture, G channel
material.normalmap	normalTexture
material.occlusionmap, R channel	occlusionTexture, R channel
material.emissivemap	emissiveTexture, RGB channels
material.emissive.{r\|g\|b}	emissiveFactor, RGB components
material.opacitymap.mode	alphaMode
material.opacitymap.cutoff	alphaCutoff

Rendering, Import, and Export

For asset & generated model preview, importing and exporting the generated models, the material attributes need to be mapped to and from the respective format. The following table shows what format implements which feature. Please note that this table only lists the formats relevant for CGA, not general CityEngine.

Basic Material Attributes

		Extensions	name	shader	color	colormap	dirtmap
Display	Asset Preview / 3D Viewport		✘	✔ (1)	✔ (2)	✔ (2)	✔ (2)
Import	Khronos Collada	.dae/.kml/.kmz	✔	✘	✔ (3)	✔ (3)	✔
	Autodesk DWG	.dwg	✘	✘	✔	✔	✘
	Autodesk FBX	.fbx	✔	✘	✔	✔	✔
	Khronos glTF	.gltf/.glb	✔	✘	✔	✔	✘
	buildingSMART IFC	.ifc	✘	✘	✔	✘	✘
	Wavefront OBJ	.obj	✔	✘	✔	✔	✘
	Universal Scene Description (USD)	.usda/.usdc/.usdz	✘	✘	✔	✔	✘
Export	Alembic	.abc	✔	✔	✔	✔	✔
	Khronos Collada	.dae/.kml/.kmz	✔	✘	✔ (3)	✔ (3)	✔
	Autodesk DWG	.dwg	✘	✘	✔	✔	✘
	Autodesk FBX	.fbx	✔	✘	✔	✔	✔
	Esri FileGDB	.gdb	✘	✘	✔	✔	✘
	Khronos glTF	.gltf/.glb	✔	✘	✔	✔	✘
	buildingSMART IFC	.ifc	✘	✘	✔	✘	✘
	Wavefront OBJ	.obj	✔	✘	✔	✔	✘
	Scene Layer Package (SLPK)	.slpk	✘	✘	✔	✔	✘
	Unreal Datasmith	.udatasmith	✔	✔	✔	✔	✔
	Universal Scene Description (USD)	.usdc/.usdz	✔	✔ (4)	✔ (5)	✔	✘
	Vue	.vob	✔	✘	✔	✔	✔

For the CityEngine viewport, the shader name is used to switch between standard and PBR rendering, see the PBR Material Attributes section above.
In the CityEngine viewport, the colormap and dirtmap values are multiplied with the (diffuse) color.
The official COLLADA standard does not support a diffuse solid color and a diffuse texture at the same time.
The USD exporter always creates an USDPreviewSurface shader. If the shader name is set to PBR, the PBR attributes will be exported as well (see PBR Material Attributes above).
If a map is present the corresponding scalar value is ignored.

Advanced Material Attributes

		opacity	opacitymap	opacitymap.mode	opacitymap.cutoff	normalmap	doubleSided
Display	Viewport	✔	✔	✔	✔	✔	✘
Import	Collada	✔	✔	✘	✘	✔	✔ (7)
	DWG	✔	✔	✘	✘	✘	✘
	FBX	✔	✔	✘	✘	✔	✘
	glTF	✔	✔	✔	✔	✔	✔
	IFC	✔	✘	✘	✘	✘	✘
	OBJ	✔	✔	✘	✘	✘	✘
	USD	✔	✔	✔	✔	✔	✘
Export	Alembic	✔	✔	✔	✘	✔	✘
	Collada	✔	✔	✘	✘	✔	✘
	DWG	✔	✔	✘	✘	✘	✘
	FBX	✔	✔	✘	✘	✔	✘
	FileGDB	✔	✘	✘	✘	✘	✔
	glTF	✔	✔	✔	✔	✔	✔
	IFC	✔	✘	✘	✘	✘	✘
	OBJ	✔	✔	✘	✘	✘	✘
	SLPK	✔	✔	✘	✘	✔	✘
	Unreal	✔	✔	✔	✘	✔	✘
	USD	✔ (5)	✔	✔	✔	✔	✘
	Vue	✔	✔	✘	✘	✘	✘

If a map is present the corresponding scalar value is ignored.
Collada does not support the "doubleSided" parameter directly. The importer only sets it to false if the Collada file was written by "SketchUp" with the "two-sided" export option enabled (= all faces are duplicated).

Legacy Material Attributes

		ambient	specular	specularmap	reflectivity	shininess	bumpValue	bumpMap
Display	Viewport	✔	✔	✔	✔	✔	✔	✔
Import	Collada	✔	✔	✔	✔	✔	✔	✔
	DWG	✔	✔	✔	✔	✔	✔	✔
	FBX	✔	✔	✔	✔	✔	✘	✔
	glTF	✘	✘	✘	✘	✘	✘	✘
	IFC	✘	✘	✘	✘	✘	✘	✘
	OBJ	✔	✔	✔	✘	✔	✔	✔
	USD	✘	✘	✘	✘	✘	✘	✘
Export	Alembic	✔	✔	✔	✔	✔	✔	✔
	Collada	✔	✔	✔	✔	✔	✔	✔
	DWG	✔	✔	✔	✔	✔	✔	✔
	FBX	✔	✔	✔	✔	✔	✘	✔
	FileGDB	✘	✘	✘	✘	✘	✘	✘
	glTF	✘	✘	✘	✘	✘	✘	✘
	IFC	✘	✘	✘	✘	✘	✘	✘
	OBJ	✔	✔	✔	✘	✔	✔	✔
	SLPK	✔	✘	✘	✘	✘	✘	✘
	Unreal	✔	✔	✔	✔	✔	✔	✔
	USD	✘	✘	✘	✔	✔	✔	✔
	Vue	✘	✔	✔	✘	✘	✘	✘

Physically-Based Rendering Material Attributes

		emissive	emissivemap	metallic	metallicmap	roughness	roughnessmap	occlusionmap
Display	Viewport	✔	✔	✔	✔	✔	✔	✔
Import	Collada	✘	✘	✘	✘	✘	✘	✘
	DWG	✘	✘	✘	✘	✘	✘	✘
	FBX	✘	✘	✘	✘	✘	✘	✘
	glTF	✔	✔	✔	✔	✔	✔	✔
	IFC	✘	✘	✘	✘	✘	✘	✘
	OBJ	✘	✘	✘	✘	✘	✘	✘
	USD	✔	✔	✔	✔	✔	✔	✔
Export	Alembic	✔	✔	✔	✔	✔	✔	✔
	Collada	✘	✘	✘	✘	✘	✘	✘
	DWG	✘	✘	✘	✘	✘	✘	✘
	FBX	✘	✘	✘	✘	✘	✘	✘
	FileGDB	✘	✘	✘	✘	✘	✘	✘
	glTF	✔	✔	✔	✔	✔	✔	✔
	IFC	✘	✘	✘	✘	✘	✘	✘
	OBJ	✘	✘	✘	✘	✘	✘	✘
	SLPK	✔	✔	✔	✔	✔	✔	✔
	Unreal	✔	✔	✔	✔	✔	✔	✔
	USD	✔	✔	✔ (5)	✔	✔ (5)	✔	✔
	Vue	✘	✘	✘	✘	✘	✘	✘

If a map is present the corresponding scalar value is ignored.

Map Transform Material Attributes

		map.tu/.tv	map.su/.sv	map.rw
Display	Viewport	✔	✔	✔
Import	Collada	✘	✘	✘
	DWG	✘	✘	✘
	FBX	✘	✘	✘
	glTF	✔ (6)	✔ (6)	✔ (6)
	IFC	✘	✘	✘
	OBJ	✘	✔	✘
	USD	✔	✔	✔
Export	Alembic	✘	✘	✘
	Collada	✘	✘	✘
	DWG	✘	✘	✘
	FBX	✔	✔	✔
	FileGDB	✘	✘	✘
	glTF	✔ (6)	✔ (6)	✔ (6)
	IFC	✘	✘	✘
	OBJ	✘	✘	✘
	SLPK	✘	✘	✘
	Unreal	✔	✔	✔
	USD	✔	✔	✔
	Vue	✔	✔	✘

Transforms are read and written using the KHR_texture_transform extension.

Example

 
attr wallC       = "#FFFFFF"
attr wallTexture = "facade/walls/wall.c.09.tif"
attr dirtTexture = "dirtmaps/dirtmap.16.tif"
...
Wall --> 
    primitiveCube() color(wallC)
    set(material.colormap, wallTexture) projectUV(0)
    set(material.dirtmap, dirtTexture) projectUV(2)