The Point Light emits light equally in all directions, similar to a light bulb or a candle flame as all rays originate from a single point. Point lights obey the physical law of inverse square falloff for intensity. As with all Items, the Point Light controls are located on the Properties tab when the light is selected. Point lights have Position and Rotation options as well as controls for the intensity of the light, shadow type, and other settings covered fully below. To control the lights color, shadow color and other material related properties, refer to the Light Material page of the documentation.
Point Light
Name: This data field displays the current item name. Users may easily change it by LMB-clicking within the field and typing the new name.
Transform--
Position: An Item transform that allows the user to numerically position the light item in XYZ space. By default, Position transforms originates from the items center position.
Rotation: An Item transform that allows the user to numerically set the rotation of the light item. By default, Rotation transforms originates from items center position. Since Point Lights radiate omni-directionally, rotation has no effect this type of light.
Order: Allows the user to set the order that rotations are applied to the light item. Changing the order that rotations are applied can sometimes help to reduce or eliminate gimbal lock.
Reset: Resets the selected transform values to (0,0,0) returning the items back to the world space center position.
Zero: Returns the light items Center position to the world space center (0,0,0) without changing the position of the light item itself.
Add: Transform Items are the channel groups associated to an item that store its transform values, controlling its position, rotation and/or scale. By default, new items do not have any transform items associated with them (even though they are visible here within the Properties panel). This is useful as an optimization as only the necessary transforms are added on an as-needed basis, reducing scene overhead. There are several ways to add them. One is by simply transforming the target item with one of the various transform tools (or by editing the values input fields). This action will cause the particular transform item to be added automatically to the 'Channels' viewport list. The 'Add' function here can also be used to add the selected set of transforms to the Channel list while keeping the default 0,0,0 values (a necessary step for 'Referencing', in order to override the channels, they must first exist).
Point Light--
Render: This drop down menu allows the user to select from 3 choices, when set to 'Default', the user can enable/disable lights using the visibility function "
" of the item list. When the light is visible, it contributes to the final rendered scene and when invisible, it will not. On some instances the user may prefer to fix this state, setting the light as 'On' (enabled) or 'Off' (disabled) regardless of visibility. Also useful for workflows that auto toggle visibility, saving the user from manually enabling lights for test renders.
Dissolve: When the 'Dissolve' function is set to any value above 0%, the lights overall affect on the scene will attenuate as the value increases. When set to 100%, the lights effect on the scene is completely disabled. This function providing a convenient way to dim a lights effect within a scene.
Radiant Intensity: This value controls the intensity of the light and uses the standard physically based unit of Watts per volumetric meter. As you would expect, increasing this value will increase the amount of light coming from the Point Light and decreasing the value reduces the light intensity. With Point lights, the area of light generated in the scene is very small and therefore large values are likely necessary to illuminate the scene how the user would expect.
TIP: Keep in mind that a lights intensities and falloffs adhere to real world scale values, scenes that do not adhere to a real world scale factor will likely require intensities to be adjusted appropriately to acheive appropriate illumination.
Falloff Type: Light in the real world isn't a uniform brightness, its intensity diminishes with distance. Photographers will be familiar with the concept that a light will be a quarter as bright at twice the distance away, know as the Inverse Square Law. MODO lights default to this setting providing a realistic way to light a scene, however there are times when users may not wish to have this behavior, so MODO provides three falloff type options-
None- No falloff, light is consistently bright across its distance.
Inverse Distance- Light is half as bright at twice the distance.
Inverse Distance Squared- Default behavior, Light will be a quarter as bright at twice the distance.
Shadow Type: This popup offers options between 'Ray Traced' , 'None' and 'Deep Shadow Maps'. In situations where users want a light to cast a shadow, Ray Traced will give the most accurate results. The traditional hard edge of ray traced shadows can easily be softened using 'Spread Angle' value in any light item. Deep Shadow maps are useful for volumetric lights and fur rendering, where a great deal of calculations are required to produce shadows; producing similar results to ray traced shadows while reducing the number of calculations.
Shadow Map Res: The 'Shadow Map Res' Sets the resolution for the calculated deep shadow map in pixels. This option is only available when Deep Shadow Map is selected.
Control Light Linking: Illumination on a surface is generally controlled by the 'Shader' item in the Shader Tree. Within the Shader it is possible to control a lights affect on a surface with Light Linking. As its name describes, it links the illumination affects of a Group of Lights to specific Items or Material Groups. When the 'Control Light Linking' option is enabled on a Light item, it will act as an individual Light Specific override to the Shader, allowing users to 'Include' or 'Exclude' a specific lights illumination on a group of items.
Item Group: The 'Item Group' option determines the specific Group of item layers in the scene that will be affected by the Light Linking. The Group needs to be defined in the Groups viewport panel. This can be done easily by selecting the target items while in 'Items' mode and then in the Groups palette LMB+click the 'New Group' button. Define a name for the group in the pop-up dialogue and choose the 'From Selected Items' option and click 'OK' to accept. Once the Group is defined, select the named group here.
Mode: The 'Mode' option determines whether the light will be 'Included' meaning it will only affect the Items in the specified Item Group, and 'Excluded' by all other surfaces, meaning it will be ignored by any items in the specified Item Group.
Radius: The default value of 0m results in crisp hard-edged shadows. Increasing the size prompts MODO to sample lighting from an array of positions within the defined radius, the various samples are blended together producing the soft edged result. Keep in mind that increasing this value too high will result in noisy shadows unless the user also increases the number of samples.
|
|
|
|
Samples: As the Spread Angle increases, additional samples are required to smooth out the resulting soft edge shadow. If the shadow appears grainy, increasing this sample setting is the most likely solution. The default value of 16 is a good starting point for balancing speed and quality. As the spread increases or the resolution of the image increases you can drive this number higher to account for any grain that appears. Keep in mind that increasing the number of samples will also increase render times.
Simple Shading: When generating soft shadows with a radius greater than 0m, MODO calculates the shadow as if sampled from an array of lights, these samples are blended together to produce the smooth result. With the 'Simple Shading' checkbox enabled, MODO will calculate the specular and diffuse values for a surface as if the light were a single point, regardless of the radius size. However, with 'Simple Shading' disabled, MODO uses the same light array as the shadow to calculate the specular and diffuse values. This results in diffuse and specular shading that is 'soft', like the shadow but can also become increasingly grainy with a greater 'Radius' value. Increasing the number of 'Samples' will reduce grain in the diffuse and specular shading as well as the shadows at the expense of longer render times.
Volumetrics--
When light shines on particular matter suspended in the air, such as water vapor, smoke or even pollution, the light rays become visible. In computer graphics this effect is known as volumetric lights, their affect can be subtle or pronounced, either way it can add a good amount of believability and atmosphere to renders. Additional Settings related to volumetrics can be found in the Light Material.
Volumetrics Checkbox: The 'Volumetrics' checkbox toggles the effect on or off. When enabled, the sample, height, and radius options become available.
Samples: Any objects that intersect the light beam volume will cast shadows through it. You may have witnessed this when sunlight shining through the clouds creates streaks of light sometimes referred to as 'god rays'. The 'Sample' setting defines the degree of accuracy that MODO uses to calculate these shadows through the volume, higher numbers of samples will give smoother and more accurate results, while lower values will render more quickly but become increasingly grainy. The sample below demonstrates the difference between 32 samples on the left and 256 samples on the right.
| 
|
Sphere Radius: This is the size of the volume overall as measured from the lights center positions extending out in all directions around the source. A setting of 10m will produce a sphere with an overall radius of 20m including falloff.
