Difference between revisions of "Grass Clump"

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m (Replaced Transform, Angular Position, & Import GUI images with more accurate versions.)
 
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[[Image:drex_module_192_image_0.png|center|Grass Clump]]
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[[File:Grass_00_GUI.png|none|470px|Grass Clump]]
  
'''Node Description and Purpose:'''<br />
 
The Grass Clump object creates, as the name suggests, a clump of grass. The clump is round. The grass is made up of individual blades. The blades are denser toward the center of the clump. It's a simple but effective object. It might not stand up to close scrutiny but it's good for near middle to far distances.
 
  
Although a surface shader is created for the clump when the node is created the surface just has a grey default colour. You will need to change it to an appropriate colour.
+
== Overview ==
 +
The Grass Clump object creates a unique clump of grass. The clump is round and the grass is made up of individual blades which are denser toward the center of the clump. While this object might not stand up to close-up scrutiny, it’s good for near-middle to far distances.
 +
Note that the surface shader setting is assigned a Default shader with grey colour values at the time the grass clump is created. You will need to change it to an appropriate colour.
  
 +
'''Settings'''
  
'''Node Type:''' Object<br />
+
*'''Name:''' This setting allows you to apply a descriptive name to the node, which can be helpful when using multiple Grass Clump nodes in a project.
 +
*'''Enable:''' When checked, the node is active and the grass clump object will appear in the scene with the settings below applied to its surface. When unchecked, the node is ignored.
  
 +
*'''Population mode:''' This popup has two options:
 +
<ul>
 +
[[File:OBJReader_01_PopulationMode.png |None|322px|Population mode options]] <br /n>
 +
<u>Individual Object:</u> This is the default for grass clumps created individually, not part of a population. If you choose this option for grass clump objects that are part of a population the population instances will still render but the grass clump object itself will also show up at its original position. <br /n>
 +
<u>Member of a Population:</u> This is the default for grass clump objects created as part of creating a population. It means the grass clump objects only render as part of a population. If you choose this option for an individual grass clump object it won't render. If you create a grass clump object as part of a population and then decide to use it on its own you may need to change the popup to Individual Object to get it to render.
 +
[[File:Grass_10_GrassClumpMemberOfPop.jpg|none|800px|Multiple grass clump populations]]
 +
</ul>
 +
 +
*'''Preview mode:'''  This popup has five options to let you choose how the object should be displayed in the 3D Preview, and sets the most detailed mode that the object can be displayed in. The Object Display Mode button in the 3D Preview controls the mode for the preview as a whole. For example, if you set the Preview mode of the object to Wireframe but the 3D Preview object display mode is set to Show as bounding boxes then the object will only be drawn as a bounding box.
 +
<ul>
 +
[[File:OBJReader_02_PreviewMode.png |none|234px|Preview mode options]]
 +
</ul>
 +
 +
*'''Preview colour:''' Enabling this parameter causes the grass clump object to be drawn in the 3D preview using the preview colour when the grass clump object display mode is set to Show as bounding box or Show as wireframe. When set to Show as smooth shaded or Show as textured the preview colour tints the grass clump object’s textured surface. This is useful for making a particular grass clump object stand out in the 3D preview. Clicking on the colour swatch to the right of the parameter label opens the [[Colour Picker]] pane.
 +
 +
 +
==Grass Clump Tab==
 +
[[File:Grass_01_GrassClumpTab.png|none|470px|Grass Clump Tab]]
 +
 +
*'''Number of blades:''' This sets the number of grass blades in the clump.
 +
<ul>
 +
{|
 +
|-
 +
| [[File:Grass_04_NumberBlades.jpg|none|800px|Number of blades per clump comparison for individual clump of grass.]]
 +
|-
 +
| [[File:Grass_07_NumberBladesPop.jpg|none|800px|Number of blades per clump comparison for grass clump population.]]
 +
|}
 +
</ul>
 +
 +
*'''Clump diameter:''' This sets the diameter of the clump.
 +
<ul>
 +
{|
 +
|-
 +
| [[File:Grass_05_ClumpDiameter.jpg|none|800px|Clump diameter comparison for individual clump of grass.]]
 +
|-
 +
| [[File:Grass_08_ClumpDiameterPop.jpg|none|800px|Clump diameter comparison for grass clump population.]]
 +
|}
 +
</ul>
 +
 +
*'''Blade length:''' This sets the maximum length, or height, of the grass blades. The blades are given random lengths up to this value.
 +
<ul>
 +
{|
 +
|-
 +
| [[File:Grass_06_BladeLength.jpg|none|800px|Blade length comparison for individual clump of grass.]]
 +
|-
 +
| [[File:Grass_09_BladeLengthPop.jpg|none|800px|Blade length comparison for grass clump population.]]
 +
|}
 +
</ul>
 +
 +
 +
==Surface Shaders Tab==
 +
[[File:Grass_02_SurfaceShaderTab.png|none|470px|Surface Shaders Tab]]
 +
 +
This tab lets you assign a surface shader to texture the grass clump object.
 +
 +
*'''Surface shader: ''' Use this setting to assign a surface shader to the grass clump object.
 +
<ul>
 +
{|
 +
|-
 +
| [[File:Grass_11_SurfaceShader.jpg|none|800px|A Visualise Tex Coordinates shader and Image Map shaders assigned to surface shader setting.]]
 +
|-
 +
| [[File:Grass_12_SurfaceShaderPop.jpg|none|800px|A Visualise Tex Coordinates shader and Image Map shaders assigned to surface shader setting.]]
 +
|}
 +
</ul>
 +
 +
*'''Displacement tolerance:'''  If you find that rough or spikey surfaces are showing problems at bucket edges, for example spikes having cut off tops, or gaps in ray traced shadows then increasing this value may help. However this can greatly increase render times. Relatively flat surfaces may render more quickly with smaller values. The default value is 1. However this is an advanced setting and you should not change it unless you have specific problem you need to address. If you are having problems try starting with 2 and then increase it by small increments until they're resolved. A value of 4 would be considered a high value.
 +
 +
*'''Smooth polygons at terminator:'''  This fixes self-shadow artifacts at the lighting terminator of polygonal objects where the smooth normals are inconsistent with the geometric normal. This parameter is enabled by default.
 +
 +
*'''Darken bumps at terminator: '''This setting approximates self-shadow of bump maps at the lighting terminator to reduce the chance of seeing a sharp line where the surface falls into shadow. This setting is enabled by default.
 +
<ul>
 +
{|
 +
|-
 +
| [[File: OBJReader_49_SmoothPolysAtTerminator.jpg |none|400px|Smooth polygons at terminator comparison]] || [[File: OBJReader_50_DarkenBumpsAndSmoothPolys.jpg |none|400px|Darken bumps at terminator comparison]]
 +
|}
 +
</ul>
 +
 +
 +
==Rendering Tab==
 +
[[File:Grass_03_RenderingTab.png|none|470px|Rendering Tab]]
 +
 +
*'''Render: ''' An object's render state can be set to Visible, Invisible or Holdout. When set to Holdout, an object is visible in the rendered image as a black shape with an alpha value of zero. When using render layers the object's render state is combined with the group visibility parameter to determine its least visible setting. Invisible is less visible than Holdout, which is less visible than Visible.
 +
<ul>
 +
[[File: OBJReader_25_RenderingTab_RenderType.png |none|148px|Render options ]]
 +
</ul>
 +
 +
*'''Visible to other rays:''' When enabled, the grass clump object will be taken into account by all the rays determined by the renderer including those from the camera, direct and indirect lighting, etc. In the example below, a 100% reflective 3D object has been placed behind three coloured spheres in order to mirror the effect of the calculated rays.
 +
<ul>
 +
[[File: OBJReader_60_RenderingTab_VisibleToOtherRays.gif | none|400px|Visible to other rays comparison]]
 +
</ul>
 +
 +
*'''Cast shadow:''' When checked, the grass clump object will cast shadows.
 +
<ul>
 +
[[File: OBJReader_61_RenderTab_CastShadows.gif | none|400px|Cast Shadows comparison]]
 +
</ul>
  
'''Settings:'''<br />
+
*'''Double-sided surface:''' When checked, the grass clump object surfaces are double sided. A single sided surface is only visible from the "front", which is the direction the surface normal is pointing. If you look at it from the other direction the surface isn't visible. Double sided surfaces are visible from all directions.
  
 +
*'''Use smooth normals:''' When checked, the grass clump object normals are interpolated to make the surface appear smooth. When unchecked, its surface will look faceted
 +
 +
*'''Render method:''' This popup has three options.
 
<ul>
 
<ul>
<li>
+
[[File: OBJReader_36_RenderingTab_RenderMethod.png |none|340px|Render method options]]
'''Population mode:''' TBC
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<u>Default: </u> Ray Tracing is the default rendering method for an object. Typically it results in higher quality and faster rendering. When displacement is applied to a 3D object the render method should be changed to Force Displacement. When the object's render method is set to Default, the object is rendered according to the Ray trace objects setting in the render node. <br /n>
</li><li>
+
 
'''Preview mode:''' This popup lets you choose how the object should be displayed in the 3D Preview. This popup sets the most detailed mode that the object can be displayed in. The Object Display Mode button in the 3D Preview controls the mode for the preview as a whole. For example if you set the '''Preview mode''' of the object to Wireframe but the 3D Preview object display mode is set to '''Show as bounding boxes''' then the object will only be drawn as a bounding box.
+
<u>Force Displacement: </u> When enabled for the grass clumpp object, its surfaces will be subdivided into micropolygons at render time, which allows the 3D geometry to be displaced correctly but at the expense of slightly longer render times. It is useful when you have some objects you want to render with displacement but you don't want to change how all the rest of your objects are rendered, i.e. Ray traced. <br /n>
</li><li>
+
 
'''Visible to camera:''' If this is checked the grass clump is visible to cameras such as the render camera. In other words it will show up in renders. If this is unchecked the grass clump won't show up in renders. However if, for example, the '''Cast shadows''' checkbox is checked then the shadows cast by the grass clump will still be visible.
+
<u>Force Ray Trace:</u> When enabled for the grass clump object, its surfaces will be ray traced at render time, even if Ray trace objects is disabled in the Renderer settings. This can be useful when Ray trace objects is disabled in the Renderer in order for other 3D objects to use displacement, but you want this object to use ray tracing for the highest quality rendering and it has not been displaced.
</li><li>
 
'''Visible to other rays:''' When this is checked the grass clump is visible to various rays which are traced during rendering, such as reflection, transparency and GI rays. As an example, if this was unchecked the grass clump would not show up in reflections.
 
</li><li>
 
'''Cast shadows:''' This should be checked if you want the grass clump to cast shadows.
 
</li><li>
 
'''Double-sided surface:''' If this is checked  object surfaces are double sided. A single sided surface is only visible from the "front", which is the direction the surface normal is pointing. If you look at it from the other direction the surface isn't visible. Double sided surfaces are visible from all directions.
 
</li><li>
 
'''Use smooth normals:''' If this is checked the object normals are interpolated to make the surface appear smooth. If it's unchecked the surface will look faceted.
 
</li><li>
 
'''Flip normals:''' Check this to flip or reverse the object normals.
 
</li><li>
 
'''Number of blades:''' This sets the number of grass blades in the clump.
 
</li><li>
 
'''Clump diameter:''' Use this to set the diameter of the clump.
 
</li><li>
 
'''Blade length:''' This sets the maximum length, or height, of the grass blades. The blades are given random lengths up to this value.
 
</li>
 
 
</ul>
 
</ul>
  
 +
*'''Sorting bias (metres):''' This setting gives you control over the order in which objects are rendered when using the micropolygon renderer. This does not apply to objects being rendered with the ray tracer. A large positive value, e.g. 10,000,000 (or 1e7) will usually force the object to render first. A large negative value, e.g. -10,000,000 (or -1e7) will usually force the object to render last, or after the terrain. This can be useful when rendering large objects with displacement, such as a lake object that lies mostly below the displaced terrain. By setting the lake object’s Sorting bias (metres) value to something like -10,000,000 forces it to render after the terrain.
 +
 +
 +
==Transform Tab==
 +
[[File: TGOReader_01_TransformTab.png |none|470px|Transform Tab]]
 +
 +
*'''Translate: ''' This sets the position of the grass clump object.
 +
 +
*'''Rotate: ''' This rotates the grass clump object about its origin. The order of the values is heading, pitch then bank.
 +
 +
*'''Scale:''' This sets the scale of the grass clump object in the X, Y and Z directions.
 +
 +
 +
== Angular Position Tab==
 +
[[File: TGOReader_02_AngularPositiontTab.png | none|470px|Angular Position Tab]]
 +
 +
This tab has settings which use angles and distance to set the position of the grass clump relative to the scene origin. These settings are an alternative to using the Translate setting in the Transform tab. The diagram below shows how all the parameters relate to each other and the origin.
 +
 +
*'''Heading:''' This angle sets the rotation of the grass clump object around the scene origin, in the XY plane, increasing as you turn clockwise.
  
<u>Transform tab</u><br />
+
*'''Elevation:''' This angle sets the vertical part of the position. You could think of it as the angle above or below the horizon. 90 is straight up, -90 is straight down.
  
 +
*'''Distance:''' This sets the distance of the grass clump object from the origin, in metres.
 
<ul>
 
<ul>
<li>
+
[[File: Angular_position.gif |none|218px|Angular positions]]
'''Translate:''' This sets the position of the object.
 
</li><li>
 
'''Rotate:''' This rotates the object about its origin. The order of the values is heading, pitch then bank.
 
</li><li>
 
'''Scale:''' You can use this parameter to scale the object in the X, Y and Z directions.
 
</li><li>
 
'''Import chan file:''' Clicking this button allows you to import a .chan file for animating the object position and rotation.
 
</li>
 
 
</ul>
 
</ul>
  
==Additional tabs for Grass Clump==
 
  
* [[Grass Clump - Angular Position Tab]]
+
==Import Tab==
 +
[[File:TGOReader_03_ImportTab.png |none|470px|Import Tab]]
 +
 
 +
These settings apply to .chan/.mov and FBX import.
 +
 
 +
*'''Import offset:''' This setting allows you to offset the positions imported from the file. As an example, you might want the positions imported from the file to be moved 10 metres in the X direction. To do that enter 10 for the X coordinate and import the file.
 +
*'''Import scale:''' You can use this setting to scale values imported from the file.
 +
*'''Import chan file:''' This setting specifies the file to be imported. When you choose a new file you will be prompted to import the file. If you choose not to import it immediately you can click the Import chan File button to perform the import.
 +
 
 +
 
 +
<br /n>
 +
 
  
* [[Grass Clump - Surface Shaders Tab]]
 
  
  
 
[[Category: Object Nodes]]
 
[[Category: Object Nodes]]

Latest revision as of 23:40, 11 October 2021

Grass Clump


Overview[edit]

The Grass Clump object creates a unique clump of grass. The clump is round and the grass is made up of individual blades which are denser toward the center of the clump. While this object might not stand up to close-up scrutiny, it’s good for near-middle to far distances. Note that the surface shader setting is assigned a Default shader with grey colour values at the time the grass clump is created. You will need to change it to an appropriate colour.

Settings

  • Name: This setting allows you to apply a descriptive name to the node, which can be helpful when using multiple Grass Clump nodes in a project.
  • Enable: When checked, the node is active and the grass clump object will appear in the scene with the settings below applied to its surface. When unchecked, the node is ignored.
  • Population mode: This popup has two options:
    Population mode options
    Individual Object: This is the default for grass clumps created individually, not part of a population. If you choose this option for grass clump objects that are part of a population the population instances will still render but the grass clump object itself will also show up at its original position.
    Member of a Population: This is the default for grass clump objects created as part of creating a population. It means the grass clump objects only render as part of a population. If you choose this option for an individual grass clump object it won't render. If you create a grass clump object as part of a population and then decide to use it on its own you may need to change the popup to Individual Object to get it to render.
    Multiple grass clump populations
  • Preview mode: This popup has five options to let you choose how the object should be displayed in the 3D Preview, and sets the most detailed mode that the object can be displayed in. The Object Display Mode button in the 3D Preview controls the mode for the preview as a whole. For example, if you set the Preview mode of the object to Wireframe but the 3D Preview object display mode is set to Show as bounding boxes then the object will only be drawn as a bounding box.
    Preview mode options
  • Preview colour: Enabling this parameter causes the grass clump object to be drawn in the 3D preview using the preview colour when the grass clump object display mode is set to Show as bounding box or Show as wireframe. When set to Show as smooth shaded or Show as textured the preview colour tints the grass clump object’s textured surface. This is useful for making a particular grass clump object stand out in the 3D preview. Clicking on the colour swatch to the right of the parameter label opens the Colour Picker pane.


Grass Clump Tab[edit]

Grass Clump Tab
  • Number of blades: This sets the number of grass blades in the clump.
    Number of blades per clump comparison for individual clump of grass.
    Number of blades per clump comparison for grass clump population.
  • Clump diameter: This sets the diameter of the clump.
    Clump diameter comparison for individual clump of grass.
    Clump diameter comparison for grass clump population.
  • Blade length: This sets the maximum length, or height, of the grass blades. The blades are given random lengths up to this value.
    Blade length comparison for individual clump of grass.
    Blade length comparison for grass clump population.


Surface Shaders Tab[edit]

Surface Shaders Tab

This tab lets you assign a surface shader to texture the grass clump object.

  • Surface shader: Use this setting to assign a surface shader to the grass clump object.
    A Visualise Tex Coordinates shader and Image Map shaders assigned to surface shader setting.
    A Visualise Tex Coordinates shader and Image Map shaders assigned to surface shader setting.
  • Displacement tolerance: If you find that rough or spikey surfaces are showing problems at bucket edges, for example spikes having cut off tops, or gaps in ray traced shadows then increasing this value may help. However this can greatly increase render times. Relatively flat surfaces may render more quickly with smaller values. The default value is 1. However this is an advanced setting and you should not change it unless you have specific problem you need to address. If you are having problems try starting with 2 and then increase it by small increments until they're resolved. A value of 4 would be considered a high value.
  • Smooth polygons at terminator: This fixes self-shadow artifacts at the lighting terminator of polygonal objects where the smooth normals are inconsistent with the geometric normal. This parameter is enabled by default.
  • Darken bumps at terminator: This setting approximates self-shadow of bump maps at the lighting terminator to reduce the chance of seeing a sharp line where the surface falls into shadow. This setting is enabled by default.
    Smooth polygons at terminator comparison
    Darken bumps at terminator comparison


Rendering Tab[edit]

Rendering Tab
  • Render: An object's render state can be set to Visible, Invisible or Holdout. When set to Holdout, an object is visible in the rendered image as a black shape with an alpha value of zero. When using render layers the object's render state is combined with the group visibility parameter to determine its least visible setting. Invisible is less visible than Holdout, which is less visible than Visible.
    Render options
  • Visible to other rays: When enabled, the grass clump object will be taken into account by all the rays determined by the renderer including those from the camera, direct and indirect lighting, etc. In the example below, a 100% reflective 3D object has been placed behind three coloured spheres in order to mirror the effect of the calculated rays.
    Visible to other rays comparison
  • Cast shadow: When checked, the grass clump object will cast shadows.
    Cast Shadows comparison
  • Double-sided surface: When checked, the grass clump object surfaces are double sided. A single sided surface is only visible from the "front", which is the direction the surface normal is pointing. If you look at it from the other direction the surface isn't visible. Double sided surfaces are visible from all directions.
  • Use smooth normals: When checked, the grass clump object normals are interpolated to make the surface appear smooth. When unchecked, its surface will look faceted
  • Render method: This popup has three options.
    Render method options

    Default: Ray Tracing is the default rendering method for an object. Typically it results in higher quality and faster rendering. When displacement is applied to a 3D object the render method should be changed to Force Displacement. When the object's render method is set to Default, the object is rendered according to the Ray trace objects setting in the render node.

    Force Displacement: When enabled for the grass clumpp object, its surfaces will be subdivided into micropolygons at render time, which allows the 3D geometry to be displaced correctly but at the expense of slightly longer render times. It is useful when you have some objects you want to render with displacement but you don't want to change how all the rest of your objects are rendered, i.e. Ray traced.

    Force Ray Trace: When enabled for the grass clump object, its surfaces will be ray traced at render time, even if Ray trace objects is disabled in the Renderer settings. This can be useful when Ray trace objects is disabled in the Renderer in order for other 3D objects to use displacement, but you want this object to use ray tracing for the highest quality rendering and it has not been displaced.

  • Sorting bias (metres): This setting gives you control over the order in which objects are rendered when using the micropolygon renderer. This does not apply to objects being rendered with the ray tracer. A large positive value, e.g. 10,000,000 (or 1e7) will usually force the object to render first. A large negative value, e.g. -10,000,000 (or -1e7) will usually force the object to render last, or after the terrain. This can be useful when rendering large objects with displacement, such as a lake object that lies mostly below the displaced terrain. By setting the lake object’s Sorting bias (metres) value to something like -10,000,000 forces it to render after the terrain.


Transform Tab[edit]

Transform Tab
  • Translate: This sets the position of the grass clump object.
  • Rotate: This rotates the grass clump object about its origin. The order of the values is heading, pitch then bank.
  • Scale: This sets the scale of the grass clump object in the X, Y and Z directions.


Angular Position Tab[edit]

Angular Position Tab

This tab has settings which use angles and distance to set the position of the grass clump relative to the scene origin. These settings are an alternative to using the Translate setting in the Transform tab. The diagram below shows how all the parameters relate to each other and the origin.

  • Heading: This angle sets the rotation of the grass clump object around the scene origin, in the XY plane, increasing as you turn clockwise.
  • Elevation: This angle sets the vertical part of the position. You could think of it as the angle above or below the horizon. 90 is straight up, -90 is straight down.
  • Distance: This sets the distance of the grass clump object from the origin, in metres.
    Angular positions


Import Tab[edit]

Import Tab

These settings apply to .chan/.mov and FBX import.

  • Import offset: This setting allows you to offset the positions imported from the file. As an example, you might want the positions imported from the file to be moved 10 metres in the X direction. To do that enter 10 for the X coordinate and import the file.
  • Import scale: You can use this setting to scale values imported from the file.
  • Import chan file: This setting specifies the file to be imported. When you choose a new file you will be prompted to import the file. If you choose not to import it immediately you can click the Import chan File button to perform the import.



A shader is a program or set of instructions used in 3D computer graphics to determine the final surface properties of an object or image. This can include arbitrarily complex descriptions of light absorption and diffusion, texture mapping, reflection and refraction, shadowing, surface displacement and post-processing effects. In Terragen 2 shaders are used to construct and modify almost every element of a scene.

A single object or device in the node network which generates or modifies data and may accept input data or create output data or both, depending on its function. Nodes usually have their own settings which control the data they create or how they modify data passing through them. Nodes are connected together in a network to perform work in a network-based user interface. In Terragen 2 nodes are connected together to describe a scene.

The bounding box is a box which surrounds (or bounds) an object or shader. This box shows the maximum extents of the item inside it. Sometimes abbreviated as "b-box".

A parameter is an individual setting in a node parameter view which controls some aspect of the node.

When Terragen renders, it divides the image up into buckets or tiles. Each bucket is rendered separately, allowing multiple buckets to be rendered at once. It also allows memory to be used more efficiently.

Literally, to change the position of something. In graphics terminology to displace a surface is to modify its geometric (3D) structure using reference data of some kind. For example, a grayscale image might be taken as input, with black areas indicating no displacement of the surface, and white indicating maximum displacement. In Terragen 2 displacement is used to create all terrain by taking heightfield or procedural data as input and using it to displace the normally flat sphere of the planet.