Rendering Methods - Revision history

Matt: Removed "Back to the Guide" as I'm moving things around

2019-08-10T07:28:15Z

Removed "Back to the Guide" as I'm moving things around

Matt: /* More Information */

2018-11-13T02:45:44Z

‎More Information

Matt: /* Rendering */

2018-11-13T02:44:50Z

‎Rendering

Matt: /* Raytracing */

2018-11-13T02:37:32Z

‎Raytracing

Matt: /* Micropolygon Rendering */

2018-11-13T02:34:47Z

‎Micropolygon Rendering

Matt at 05:00, 14 November 2017

2017-11-14T05:00:03Z

Matt: Changed links from http://www.planetside.co.uk/forums/index.php?topic=8300.0 to Ray_Trace_Objects_and_Defer_Atmosphere/Cloud

2017-11-14T04:58:29Z

Changed links from http://www.planetside.co.uk/forums/index.php?topic=8300.0 to Ray_Trace_Objects_and_Defer_Atmosphere/Cloud

JavaJones at 07:47, 29 September 2017

2017-09-29T07:47:14Z

Jo at 00:56, 14 January 2013

2013-01-14T00:56:53Z

Jo at 00:49, 14 January 2013

2013-01-14T00:49:28Z

← Older revision		Revision as of 07:28, 10 August 2019
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	http://en.wikipedia.org/wiki/Ray_tracing_(graphics)		http://en.wikipedia.org/wiki/Ray_tracing_(graphics)
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−	~~[[Terragen_4_User_Guide_Part_2:_Fundamental_Rendering_and_Shader_Concepts\|Back to the Guide]]~~

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 ===More Information===
-You can find some more advanced information on raytracing in TG here:
+You can find some more advanced information on raytracing in Terragen here:
 [[Ray_Trace_Objects_and_Defer_Atmosphere/Cloud|Ray Trace Objects and Defer Atmosphere/Cloud]]

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 ===Rendering===
-By default TG renders in a hybrid fashion, using both micropolygon rendering and raytracing. Micropolygon rendering is used to render the terrain, water and sky. Raytracing is used mainly as secondary rays, for reflection, lighting and shadows.
+By default Terragen renders in a hybrid fashion, using both micropolygon rendering and raytracing. Micropolygon rendering is used to render the terrain, water and the "background" object. For these kinds of surfaces, raytracing is used mainly as secondary rays, for reflection, lighting and shadows.
 An important point is that raytracing is also used as the default method for rendering objects such as imported models. This is controlled by the '''Ray trace objects''' parameter in the [[Render]] node. The reason that raytracing is used for objects is that they're effectively static data and can be rendered efficiently using the raytracer. The raytracer can give higher visual quality for a given render quality setting than can be achieved with the micropolygon renderer. To sum up, raytracing makes objects look better and render more quickly.
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 The one disadvantage to using raytracing for objects is that the raytracer doesn't support displacement. It is able to convert displacement data into bump mapping data, but bump mapping doesn't give the same visual quality as displacement. Think about a bark texture on a tree. Using displacement the tree bark can have a real 3D shape and the silhouette of the trunk would show lumps and bumps. With bump mapping the shape of the bark is faked using lighting effects. The underlying surface remains smooth but gives an impression of being a real 3D shape. However if you looked at the silhouette of the trunk you would see the flatter shape of the underlying geometry.
-If your scene requires displacement on models to look good you will want to turn off '''Ray trace objects'''. This will make objects render using the micropolygon renderer. You might also want to increase the detail and antialiasing settings for the render node.
+If your scene has a model that requires displacement to look good you will want to change the object's '''Render method''' to '''Force displacement'''. If your version of Terragen doesn't have this option you can turn off '''Ray trace objects''' on the render node, but this affects all objects in the scene. Either of these changes will make objects render using the micropolygon renderer. You might also want to increase the "micropoly detail" setting for the render node.
-You can also turn on raytracing for atmosphere rendering. This is done with the '''Ray trace atmosph.''' parameter in the Render node. This is off by default. Raytracing the atmosphere can give better quality results at lower detail settings than the micropolygon renderer, but it's not such a clear benefit as it is for rendering objects. It may take some experimentation to get the best results.
+When using raytracing for objects and/or "Defer atmo/cloud" the quality and speed is highly dependent on antialiasing and sampling settings, much more so than with micropolygon rendering. You can find more specific information about that [[Ray_Trace_Objects_and_Defer_Atmosphere/Cloud|here]].
 ===More Information===

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 You might come across node parameters with names like "Enable secondary" or "Visible to other rays". These parameters typically effect how a node interacts with secondary rays. Lets's say you had an object node and you unchecked the '''Visible to other rays''' checkbox. This would mean that even though the object was still visible to the camera it would not be hit by secondary rays. One consequence of this is that the object wouldn't show up in reflections.
-It's not really possibly to use raytracing by itself to render a scene in TG. You can do this, by turning on the '''Ray trace everything (not recommended)''' parameter in the Extra tab of the [[Render]] node. However, as the parameter name suggests, this is not recommended. A big reason for this is that the raytracer doesn't yet support displacement, or at least not efficiently. If you try it you will find that terrain renders blockily, even at high levels of detail. There are other settings you can tweak to improve the results, such as the '''Ray detail multiplier''' in the [[Render Subdiv Settings]] node, but they can greatly increase render time.
+It's not really possibly to use raytracing by itself to render a scene in TG. You can do this, by turning on the '''Ray trace everything (not recommended)''' parameter in the Extra tab of the [[Render]] node. However, as the parameter name suggests, this is not recommended. A big reason for this is that the raytracer doesn't support displacement as efficiently as the micropolygon renderer. If you try it you will find that terrain renders blockily, even at high levels of detail. There are other settings you can tweak to improve the results, such as the '''Ray detail multiplier''' in the [[Render Subdiv Settings]] node, but they can greatly increase render time.
 ===Rendering===

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 Another big advantage of a micropolygon renderer is that it's able to work with displacement efficiently. Massive amounts of displacement is one of TG's strengths. When a surface has been broken up into micropolygons each of those micropolygons can be moved in 3D space in any direction. Moving the micropolygons like this is called displacement. You can read more about displacement [[Displacement|here]].
-Micropolygon rendering is used, by default, to render the terrain, water and sky.
+Micropolygon rendering is used, by default, to render the terrain and bodies of water.
 ===Raytracing===

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 You can find some more advanced information on raytracing in TG here:
-[[Ray_Trace_Objects_and_Defer_Atmosphere/Cloud]]
+[[Ray_Trace_Objects_and_Defer_Atmosphere/Cloud|Ray Trace Objects and Defer Atmosphere/Cloud]]
 There is a lot of information available on both micropolygon and raytrace rendering, both in books and on the internet. If you want to find out more a good place to start is Wikipedia. Here's some information on micropolygons and the Reyes rendering algorithm:

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 ===Introduction===
-Terragen 2 uses two different rendering methods. One method is micropolygon rendering and the other is raytracing. It's most accurate to say that TG is a hybrid renderer, because the different rendering techniques are normally used together to render a scene. This page gives background information on the two methods and how they're used in TG.
+Terragen 4 uses two different rendering methods. One method is micropolygon rendering and the other is raytracing. It's most accurate to say that TG is a hybrid renderer, because the different rendering techniques are normally used together to render a scene. This page gives background information on the two methods and how they're used in TG.
 ===Micropolygon Rendering===
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-[[Terragen_2_User_Guide_Part_2:_Fundamental_Rendering_and_Shader_Concepts|Back to the Guide]]
+[[Terragen_4_User_Guide_Part_2:_Fundamental_Rendering_and_Shader_Concepts|Back to the Guide]]

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 Raytracing is the other rendering technique used by TG. You may already be familiar with what raytracing does as it's a common technique used in other renderers. It works by projecting lines, or rays, into the scene. When one of these rays hits an element in the scene the renderer calculates the shading of the scene element. Rays might also collect shading information on their way through the scene, when passing through clouds for example.
-There are two main types of rays. The first is primary rays. Primary rays start from the camera and are projected out into the scene through the pixels of the image. Imagine you were holding a section of screen door mesh in front of your face. A primary ray would start from your eye and then travel out into the world through one of the holes in the mesh (the equivalent of a pixel). The ray would finish where it hit some object out in front of you. Higher quality results are given by using multiple rays for each pixel in the rendered image.
+There are two main types of rays. The first is primary rays. Primary rays start from the camera and are projected out into the scene through the pixels of the image. Imagine you were holding a section of screen door mesh in front of your face. A primary ray would start from your eye and then travel out into the world through one of the holes in the mesh (the equivalent of a pixel in the rendered image). The ray would finish where it hit some object out in front of you. Higher quality results are given by using multiple rays for each pixel in the rendered image.
 The other type of ray is a secondary ray. Secondary rays begin where a primary ray hits an element in the scene. A good example of a secondary ray is a reflection ray. Let's say a primary ray hits a reflective object in the scene. We need to find both what that point on the reflective surface is actually reflecting and what colour it should be reflecting. This is found by sending a secondary ray out into the scene to see what it hits. Secondary rays are also used for things like calculating lighting and shadows.
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 http://en.wikipedia.org/wiki/Reyes_rendering
-Reyes rendering as a well known micropolygon rendering architecture made famous by Pixar's PRMan (aka RenderMan) renderer. TG doesn't use the Reyes architecture specifically, but many of the concepts are the same.
+Reyes rendering is a well known micropolygon rendering architecture made famous by Pixar's PRMan (aka RenderMan) renderer. TG doesn't use the Reyes architecture specifically, but many of the concepts are the same.
 Here's some information about raytracing: