| Blender Documentation Volume II - Reference Guide: Last modified March 29 2004 S68 | ||
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The Shading context is among the most complex, exhibiting 5 Sub-contextes and several Panels. Many of these panels are Condesed into a single Panel with Tabs in the default Blender settings.
The settings in these Sub-context visualise the Lamp DataBlock. The Lamp Buttons are only displayed if the active Object is a Lamp.
***FIG HERE***
As for all these Sub-contextes, except radiosity, the first Panel contains a preview square window.
Right of the Window a column of four Toggle Buttons allows to select the Lamp Type:
The lamp is restricted to a conical space. The 3DWindow shows the form of the spotlight with a broken line.
***FIG HERE***
The top button row presents:
If the Lamp Block is used by more than one Object, this button shows the total number of Objects. Press the button to make the Lamp "Single User". This duplicates the Lamp Block.
For the lamp types Lamp and Spot, the distance affects the intensity of the light. The standard formula is used for this:
D = "Dist" button, r = distance to the lamp. Light intensity = D/(D + r).
This is an inverse linear progression. With the option Quad, this can be changed.
Left button column presents:
The distance from the lamp is in inverse quadratic proportion to the intensity of the light. An inverse linear progression is standard (see the buttons Dist, Quad1 and Quad2).
The lamp only sheds light within a spherical area around the lamp. The radius of the sphere is determined by the Dist button.
Only Objects in the same layer(s) as the Lamp Object are illuminated. This enables you to use selective lighting, to give objects an extra accent or to restrict the effects of the lamp to a particular space. It also allows to you keep rendering times under control.
The lamp does not interact with the "Specular" shader of the object.
Right button column presents:
The intensity of the light. The standard settings in Blender assume that a minimum of two lamps are used.
The light intensity formula of a Quad Lamp is: Light intensity = D / (D + (quad1 * r) + (quad2 * r * r)) D = Dist button. r = distance to the lamp. The values of quad1 and quad2 at 1.0 produces the strongest quadratic progression. The values of quad1 and quad2 at 0.0 creates a special Quad lamp that is insensitive to distance.
***FIG HERE***
In the case of a Spot Lamp a full separate Panel is needed for additional settings. The left column contains:
The lamp can produce shadows. Shadow calculations are only possible with the Spot lamps. The render option Shadows must also be turned ON in the DisplayButtons to enable Shadows at a global level.
For spot lamps (with Shadow ON), only the shadow is rendered. Light calculations are not performed and where there are shadows, the value of Energy is reduced.
Spotlamps can have square Spotbundles with this option. For a better control over shadows and for slide projector effects.
The lamp has a halo. This only works with Spot lamps. The intensity of the halo is calculated using a conic section. With the option Halo step: it also uses the shadow buffer (volumetric rendering). The scope of the spot halo is determined by the value of Dist.
The right column contains:
The angle of the beam measured in degrees. Use for shadow lamp beams of less than 160 degrees.
Blender uses a shadow buffer algorithm. From the spotlight, a picture is rendered for which the distance from the spotlight is saved for each pixel. The shadow buffers are compressed, a buffer of 1024x1024 pixels requires, on average, only 1.5 Mb of memory.
This method works quite quickly, but must be adjusted carefully. There are two possible side effects:
Aliasing. The shadow edge has a block-like progression. Make the spot beam smaller, enlarge the buffer or increase the number of Samples in the buffer.
Biasing. Faces that are in full light show banding with a block-like pattern. Set the Bias as high as possible and reduce the distance between ClipSta and ClipEnd.
Seen from the spot lamp: everything closer than ClipSta always has light; everything farther away than ClipEnd always has shadow. Within these limits, shadows are calculated. The smaller the shadow area, the clearer the distinction the lamp buffer can make between small distances, and the fewer side effects you will have. It is particularly important to set the value of ClipSta as high as possible.
The shadow buffer is 'sampled'; within a square area a test is made for shadow 3*3, 4*4 or 5*5 times. This reduces the aliasing.
***FIG HERE***
This texture panel, and the following are a simplified version of the Material texture panels.
Left column contains:
A Lamp has six channels with which Textures can be linked. Each channel has its own mapping, i.e. the manner in which the texture works on the lamp. The settings are in the buttons described below and in the Map To Panel.
Right column contains:
Each Texture has a 3D coordinate (the texture coordinate) as input. The starting point is always the global coordinate of the 3D point that is seen in the pixel to be rendered. A lamp has three options for this.
***FIG HERE***
Normally, textures are executed one after the other and placed over each other. A second Texture channel can completely replace the first. This option sets the mapping to stencil mode. No subsequent Texture can have an effect on the area the current Texture affects.
The settings in this ButtonsWindow visualise the Material DataBlock. The Material Panels and Buttons are only displayed if the active Object has a Material.
***FIG HERE***
As for all these Sub-contextes, except radiosity, the first Panel contains a preview square window.
THe top three buttons on the left governs the preview:
In the sphere-preview the Z axis is the vertical axis for the preview sphere; the X and Y axes revolve around this axis.
***FIG HERE***
The very top row is related to the Material Data Block.
If the Material block is used by more than one Object, this button indicates the total number of users. Press the button to make the Material "Single User". An exact copy is created.
Blender assigns a "Fake" user to the material, so that it is saved in the .blend fileeven if unlinked.
The complete settings for the Material and all the mapping are copied to a temporary buffer.
The temporary buffer is copied to the Material.
These row or buttons immediately below specify what the Material block is linked to, or must be linked to. By linking Materials directly to Objects, each Object is rendered in its own Material.
This Button indicates the block to which the Material is linked. This button can only be used to give the block another name. Possible blocks are:
ME: Material is linked to a Mesh (ObData) block.
CU: Material is linked to a Curve, Surface or Font (ObData) block.
MB: Material is linked to a MetaBall (ObData) block.
OB: Material is linked to the Object itself.
Use this button to link the current Material to the Object. Any link to the ObData block remains in effect. Links can be removed with the remove link button in top row.
An Object or ObData block may have more than one Material. This button can be used to specify which of the Materials must be displayed, i.e. which Material is active. The first digit indicates how many Materials there are; the second digit indicates the number of the active Material. Each face in a Mesh has a corresponding number: the 'Material index'. The number of indices can be specified with the EditButtons. Curves and Surfaces also have Material indices.
Third row of buttons governs:
If the Mesh vertex has colours (see Vertex Paint), they are added to the Material as extra light. The colours also remain visible without lamps. Use this option to render radiosity-like models.
If the Mesh vertex has colours, this button replaces the basic colour of the Material with these colours. Now light must shine on the Material before you can see it.
This button makes the Material insensitive to light or shadow.
The block below defines at a time the Three colors of the material and the behavior of the Object in Real Time simulations. This is selected with the bottom row of Toggle Buttons:
Most colour sliders in Blender have two pre-set options: in this case, the colour is created by mixing Red, Green, Blue.
The colour sliders mix colour with the Hue, Saturation, Value system. 'Hue' determines the colour, 'Saturation' determines the amount of colour in relation to grey and 'Value' determines the light intensity of the colour.
Adjust parameters for the dynamics options. The neighbouring buttons changes completely.
For the Colours, whichever the mapping, above these Toggle Buttons there are three more Toggle Buttons on a column, with colour preview on their left:
The mirror colour of the Material. This affects a environment or reflection map.
The color, selected by its Toggle Button, can be edited with the three Num Buttons on the right which, depending on color scheme, are:
The degree of coverage, which can be used to make Materials transparent. Use the option ZTransp to specify that multiple transparent layers can exist. Without this option, only the Material itself is rendered, no matter what faces lie behind it. The transparent information is saved in an alpha layer, which can be saved as part of a picture.
***FIG HERE***
This Panel presents the Diffuse and Specular shader settings on the left and a column of Toggle Buttons on the right. On the left:
Three Diffuse Shaders are coded in Blender, depending on which is chosen the Num Buttons immediately on the right changes:
Lambert - Blender default diffuse shader since ever. Parameters:
RefStrength of reflectivity
Oren-Nayar - Blender new physical shader (v. 2.28). Parameters:
RefStrength of reflectivity
RoughRoughtness of the surface
Toon - Blender new cartoon shader (v. 2.28). Parameters:
RefStrength of reflectivity
SizeAngular width of lit region
SmoothBlurrines of light/shadow boundary
Four Specular Shaders are coded in Blender, depending on which is chosen the Num Buttons immediately on the right changes:
CookTorr - Blender default specular shader since ever. Parameters:
SpecStrength of Specularity
Hard The hardness of the specularity. A large value gives a hard, concentrated sheen, like that of a billiard ball. A low value gives a metallic sheen.
Phong - Blender Phong shader (v. 2.28). Parameters:
SpecStrength of Specularity
Hard The hardness of the specularity. A large value gives a hard, concentrated sheen, like that of a billiard ball. A low value gives a metallic sheen.
Blinn - Blender Physical shader (v. 2.28). Parameters:
SpecStrength of Specularity
Hard The hardness of the specularity. A large value gives a hard, concentrated sheen, like that of a billiard ball. A low value gives a metallic sheen.
RefrRefractive index to compute specularity. This does not include mirror-like reflections or glass-like refractions.
Toon - Blender new cartoon shader (v. 2.28). Parameters:
SpecStrength of Specularity
SizeAngular width of specular region
SmoothBlurrines of specular/diffuse boundary
The bottom four Num Buttons are:
The degree to which the global Ambient colour is applied, a simple form of environmental light. The global Ambient can be specified in the World Sub-context. Ambient is useful for giving the total rendering a softer, more coloured atmosphere.
This option adds some kind of glow to transparent objects, but only works with the unified renderer.
This button allows you to give the face to be rendered an artificial forward offset in Blender's Zbuffer system. This only applies to Materials with the option ZTransp. This option is used to place cartoon figures on a 3D floor as images with alpha. To prevent the figures from 'floating', the feet and the shadows drawn must be placed partially beneath the floor. The Zoffset option then ensures that the entire figure is displayed. This system offers numerous other applications for giving (flat) images of spatial objects the appropriate 3D placement.
The rightmost column of Toggle Buttons contains:
This buttons turns a regular material into a Halo material. both the Material and this Panel dramaticaly change. They are described below.
This specifies whether or not shadow lamps can 'see' the current Material. That is if object cast shadows.
This button determines whether the Material can receive a shadow, that is if object receive castshadows.
Only the edges of faces are rendered (normal rendering!). This results in an exterior that resembles a wire frame. This option can only be used for Meshes.
Transitional Zbuffers can only render opaque faces. Blender uses a modified method to Zbuffer transparent faces. This method requires more memory and calculation time than the normal Zbuffer, which is why the two systems are used alongside each other.
Environment option. The Material is not rendered and the Zbuffer and render buffers are 'erased' so that the pixel is delivered with Alpha = 0.0.
If a Material has the option Halo ON, a number of buttons change to specific halo settings. Lens flares can also be created here. Halos are rendered on the 3D location of the vertices. These are small, transparent round spots or pictures over which circles and lines can be drawn. They take Blender's Zbuffer into account; like any 3D element, they can simply disappear behind a face in the forefront.
Halos are placed over the currently rendered background as a separate layer, or they give information to the alpha layer, allowing halos to be processed as a post-process.
Only Meshes and Particle Effects can have halos. A Mesh with a halo is displayed differently in the 3DWindow; with small dots at the position of the vertices. Halos cannot be combined with 'ordinary' faces within one Mesh.
***FIG HERE***
As for all these Sub-contextes, except radiosity, the first Panel contains a preview square window.
The preview now show the halo material, the top three buttons on the left loose functionality, the bottom two keep the functionalities they had for normal materials.
***FIG HERE***
The two top rows related to the Material Data Block mantains the meaning they had for normal Materials. The third line disappears and the bottom part of the Panel mantains the general functionality but colors now refear to:
The base color of the Halo Ring, if any.
The color, selected by its Toggle Button, can be edited with the three Num Buttons on the right which, depending on color scheme, are:
The degree of coverage, which can be used to make Materials transparent. Use the option ZTransp to specify that multiple transparent layers can exist. Without this option, only the Material itself is rendered, no matter what faces lie behind it. The transparent information is saved in an alpha layer, which can be saved as part of a picture.
***FIG HERE***
This Panel presents the Halo shader settings on the left and a column of Toggle Buttons on the right. On the left:
Normally, the colour of halos is calculated during rendering, giving a light emitting effect. Set the "Add" value to 0.0 to switch this off and make black or 'solid' halos possible as well.
The number of rings rendered over the basic halo, if the corresponding toggle button on the right is enabled.
The number of sparkle-shaped lines rendered over the basic halo, if the corresponding toggle button on the right is enabled.
The number of points on the star-shaped basic halo, if the corresponding toggle button on the right is enabled.
'Random' values are selected for the dimension of the rings and the location of the lines based on a fixed table. Seed determines an offset in the table.
If the Halo is of Flare type, selected with toggle Button on the right, five further Num Buttons appear:
The dimension and shape of the sub Flares is determined by a fixed table with 'random' values. Fl.seed specifes an offset in the table.
Each halo is now also rendered as a lens flare. This effect suggests the reflections that occur in a camera lens if a strong light source shines on it. A Flare consists of three layers:
the ordinary halo, which has a 3D location, and can thus disappear behind a face.
the basic Flare, which is the same halo, but possibly with other dimensions. This is placed over the entire rendering as a post-process.
the sub Flares, multi-coloured dots and circles, that are also placed over the entire rendering as a post-process.
The HaloSize value not only determines the dimensions, but is also used to determine the visibility - and thus the strength - of the Flare rendered in the post-process. This way, a Flare that disappears slowly behind a face will decrease in size at a corresponding speed and gradually go out.
Instead of being rendered as a circle, the basic halo is rendered in the shape of a star. The NumBut Star determines the number of points the star has.
Halos can be given textures in two ways:
HaloTex OFF: the basic colour of each halo is determined by the texture coordinate of the halo-vertex.
HaloTex ON: each halo gets a complete texture area, in which, for example, an Image texture is displayed completely in each basic halo rendered.
The vertex normal ("Puno" in Blender's turbo language) is used to help specify the dimension of the halo. Normals that point directly at the Camera are the largest; halos with a normal that point to the rear are not rendered. If there are no vertex normals in the Mesh (the Mesh only consists of vertices) the normalised local coordinate of the vertex is used as the normal.
Material textures are the most complex in Blender. There are three panels devoted to them. This first is concernd with texture channels, the second governs the Input mapping, the last the output mapping.
***FIG HERE***
A Material has eight channels to which Textures can be linked. Each channel has its own mapping, which is the effect the texture has on the material.
Channels are grouped on a column on the left. For each active channel a Toggle button appears, allowing to switch off each single texture channel.
The up pointing arrow on the right of the Panel copies the complete mapping settings to a temporary buffer.
The down pointing arrow on the right of the Panel pastes the complete mapping settings from the temporary buffer.
***FIG HERE***
Each Texture has a 3D coordinate (the texture coordinate) as input. The starting point is generally the global coordinate of the 3D point that can be seen in the pixel to be rendered. A Material has the following Mapping options, given by the first two row of buttons:
The U-V coordinates of a face or Nurbs surface from an Object make up the texture coordinates. U-V is a commonly used term for specifying the mathematical space of a flat or curved surface.
Every Object in Blender can be used as a source for texture coordinates. For this, the Object's inverse transformation is applied to the global coordinate, which gives the local Object coordinate. This links the texture to the position, dimension and rotation of the Object. Generally, an Empty Object is used to specify the exact location of a Texture, e.g. to place a logo on the body of an airplane. Another commonly used approach is to have the 'Texture Object' move to achieve an animated texture.
The name of the Object used for the texture coordinates must be placed in this Text Button. If the Object does not exist, the button remains empty.
Sticky texture. Blender allows you to assign a texture coordinate to Meshes, which is derived from the manner in which the Camera view sees the Mesh. The screen coordinate (only X,Y) for each vertex is calculated and saved in the Mesh. This makes it appear as if the texture is projected from the Camera; the texture becomes "sticky" (see also Make Sticky in the EditButtons). Use Sticky to precisely match a 3D object with an Image Texture. Special morphing effects can also be achieved.
The screen coordinate (X,Y) is used as a texture coordinate. Use this method to achieve 2D layering of different Images.
The normal vector of the rendered face is used as a texture coordinate. Use this method to achieve reflection mapping, which is the suggestion of mirroring using a specially pre-calculated Image.
The reflection vector of the rendered face is used as a texture coordinate. This vector points in a direction that makes the face appear to be mirrored. Use this option to suggest a reflected surface with procedural textures such as "Marble" or "Clouds" and of course for the use with the EnvMap texture.
For Image Textures only; the four buttons middle left in the Panel determines the manner is which the 3D coordinate is converted to 2D.
Depending on the normal vector of the face, the X-Y or the X-Z or the Y-Z coordinates are selected. This option works well for stones, marbles and other regular textures,
The Map To Panel determines the effect of the Texture output for the current point.
***FIG HERE***
The top two rows of Buttons determines which property of the material is affected:
The texture affects the rendered normal direction. It is a three state button, effects can be off, positive or negative. Only important for Image textures. The Stucci is the only procedural texture which effectively generate normal informations (for now).
The texture affects the value of the material's reflectivity . This if a three state button: off, active and inverse.
The texture affects the value of specularity of the material. This if a three state button: off, active and inverse.
The group of buttons bottom left on the panel defines further settings on how the Texture output is handled.
Normally, textures are executed one after the other and laid over one another. A second Texture channel can completely replace the first. With this option, the mapping goes into stencil mode. No subsequent Texture can have an effect on the area the current Texture affects.
If there is an active Texture channel in a Material, Lamp or World Block, switching to Texture Sub-Context (F6) populates the Buttons Window wit Texture panels of the current Texture Block.
Each Texture has a 3D coordinate (the texture coordinate) as input, as described in the Material SUb-context. What happens in the Texture evaluation process is determined by the type of texture:
Intensity textures: return one scalar value. The preview render in this window shows this as grey values.
RGB textures: returns three, RGB, values; they always work on colour.
Bump textures: returns three values; they always work on the normal vector. Only the "Stucci" and "Image" texture can give normals.
***FIG HERE***
As for all these Sub-contextes, except radiosity, the first Panel contains a preview square window.
Right of the Window a column of three Toggle Buttons allows to select the Block of Textures, Blender automaticaly select the right one:
***FIG HERE***
The Texture Block in the top row indicate what Texture block is visualised.
If the Texture block has more than one user, this button shows the total. Press the button to make the Texture "Single User". An exact copy is then created.
Blender assigns a "Fake" user to the texture, so that it is saved in the .blend file even if unlinked.
Below the Texture Block there are three columns of buttons, on the left:
Eight or six buttons, depending if we are working on a Material, on a Lamp or on the World, showing the active Texture channes with their names.
The two columns on the right select the type of texture. There are 11 types one of which, none effectively is "no texture". Each of the other buttons select a particular kind of texture and opens atleast a new, type-dependent, Panel. Texture types will be described in the relevant Panel description
***FIG HERE***
This panel allows to create a smooth colour progression in place of an Intensity progression. Intensity textures are thus changed into an RGB texture. The use of Colorband with a sharp transistion can cause aliasing.
The position of the active colour. Values range from 0.0 to 1.0. This can also be entered using LeftMouse (hold-move) in the Colorband.
The interpolation type with which colours are mixed, i.e. 'Ease', 'Linear' and 'Spline'. The last gives the most fluid progression.
***FIG HERE***
Of the ten possible texture the Image one is the only requiring twoadditional Panels, this, and the Cropand Anim one.
The Image texture is the most frequently used and most advanced of Blender's textures. The standard bump-mapping and perspective-corrected MipMapping, filtering and anti-aliasing built into the program guarantee outstanding image quality. Because pictures are two-dimensionaal, you must specify in the mapping buttons how the 3D texture coordinate is converted to 2D; mapping is a part of the MaterialButtons. For best results UV mapping is required.
The first two row of Buttons in the Panel determines:
This option interpolates the pixels of an Image. This becomes visible when you enlarge the picture. Turn this option OFF to keep the pixels visible - they are correctly anti-aliased. This last feature is useful for regular patterns, such as lines and tiles; they remain 'sharp' even when enlarged considerably.
Generates a series of pictures, each half the size of the former one. This optimises the filtering process. When this option is OFF, you generally get a sharper image, but this can significantly increase calculation time if the filter dimension becomes large.
Video frames consist of two different images (fields) that are merged by horizontal line. This option makes it possible to work with field images. It ensures that when "Fields" are rendered the correct field of the Image is used in the correct field of the rendering. MipMapping cannot be combined with "Fields".