Visualization Guide
Visualization Guide
Visualization Guide

Define Light

Use it!

Used to access the lighting capabilities of MicroStation. The Define Light dialog box contains controls that are used to create and modify light sources for the scene. This tool also can be accessed by selecting Settings > Rendering > Source Lighting. Settings for existing light sources may be edited individually, or you can select multiple lights to edit together.

Tool SettingEffect
Mode

Sets the general type of operation to be performed using the tool:

  • Modify
    • — Modify a light source.
  • Create
    • — Create a light source.
  • Clear Shadow Map(s)
    • — (Phong rendering only) Lets you clear existing shadow maps if the design has been Phong rendered previously during the current session, or previously with Save Shadow Maps turned on in the Rendering Settings dialog box (select Settings > Rendering > General). Clears the shadow maps from memory so that they will be recomputed.
Method

(Mode set to Modify only) Sets the specific type of operation to be performed using the tool:

  • Move Light
    • — Move a light source. With directional light sources, both the location and target points are redefined separately. See “To move a light source”.
Type

(Mode set to Create only) Sets the type of light source to create: Distant Light, Point Light, Spot Light, Area Light, or Sky Opening (see “Creating Light Sources”).

Name

This text field lets you define a name for the light source that you are creating. Giving light sources unique names helps you identify them if you want to modify them in some way, or delete them. Where no name is input, MicroStation gives the light a default name that identifies the type of light source. Where other light sources of the same type, with the same name, then the name is incremented. For example, Spot Light, Spot Light (1), Spot Light (2), and so on, for Spot Light sources.

If predefined lights are available, then this field becomes a combo box with a drop-down list that lets you select from the predefined lights. You then can give the selected light a unique name and, if required, modify the settings.

On

Sets whether the light source is on or off.

Color

Opens the Modify Color dialog box, which is used to specify a color for the light source.

Shadow

If on, the light source can cast shadows in a Phong, or Ray Traced, rendered image, as well as with a Radiosity solution, or a Particle Traced image.

  • In Phong rendered images, only Distant, Area, and Spot lights can cast shadows.

  • In Ray Traced, Particle Traced, or Radiosity rendered images, all light source types can cast shadows.

Attenuate

If on, the light source is attenuated; its intensity decreases over distance.

Lumens

Sets the light source brightness, for use with ray tracing (when Real World Lighting is turned on in the Ray Tracing settings box), radiosity solving, and particle tracing. Acts as a multiplier of the light source's Color and Intensity values to simulate real world lighting values. This value, when multiplied by the Intensity of the light, specifies the overall brightness, in Lumens (see Radiosity and Lighting).

Intensity

Sets the intensity of the light source (default is 1.0) for standard rendering (up to Phong). For radiosity, particle tracing, radiosity and ray tracing that use real world lighting, acts as a multiplier to the Lumens setting.

Resolution

(Phong rendering only) Sets the resolution of the shadow map generated for the light source. The lower the value, the less resolute the shadows from the light source will be, and processing time will be reduced.

Distance

(Attenuate setting on only) Sets the distance from the light source, in working units, at which its attenuated intensity is one-half of its original intensity.

For Radiosity solutions, when Light Interpretation is set to Extended, and for all Particle Tracing solutions, the Distance value is ignored. In these cases the attenuation of lighting is relative to the square of the distance.

Cone Angle

(Type set to Spot Light only) Sets the angle of the beam cone of a spot light source. Used to “focus” the beam.

Delta Angle

(Type set to Spot Light only) Sets the angle, at the edge of the beam cone, through which a Spot Light beam falls from full intensity to zero.

Cell Scale

Controls the size of the construction light source element.

Samples

(Type set to Area Light only) Sets the number of samples to be taken when computing ray traced shadows only.

Min Samples

(Type set to Sky Opening only) Sets the minimum number of samples taken. When computing shadows from Sky Openings, the distance from the opening determines the number of shadows samples taken. When a point is very far from the opening, it can only see a small portion of the sky, and only the number of samples defined in “Min Samples” are taken.

Max Samples

(Type set to Sky Opening only) Sets the maximum number of samples taken. When computing shadows from Sky Openings, the distance from the opening determines the number of shadows samples taken. As points closer to the opening are illuminated, those points can see more of the sky and the number of shadow samples will increase, up to “Max Samples”.

Global (button)

Opens the Global Lighting dialog box, which is used to control settings for Ambient, Flashbulb, Solar, and Sky Light.

Scan (button)

(Mode set to Modify only) Starts the light scanning process (see Modifying Light Sources).

Show/Hide Light List (icon)

Located at the top right of the Define Light dialog box, clicking this icon opens/closes the Light List list box, which displays a list of all the source lights present in the design. You can use this list box to identify a light source for modification.

Show/Hide IES Data (icon)

Located at the bottom left of the Define Light dialog box, clicking this icon opens/closes the IES box that contains IES data details for the selected light source.

  • IES data
    • — If on, then IES data is used in the calculation of the light from the light source.
  • Show Webs
    • — If on, then the photometric characteristics for the IES light source are displayed graphically.
  • Show IES Detailed Text
    • — If on, a text window opens to display the Photometric Data File Information for the IES light source.
  • Rotation
    • — Lets you enter a value to rotate the photometric characteristics for the IES light source.
  • Lumens
    • — Displays the brightness value, in Lumens, for the IES light source. This setting is used in Ray Tracing (when (Real World Lighing is on), Radiosity solving and Particle Tracing only.
  • Filename (button)
    • — (IES Data on only) Clicking this button opens the Select IES lighting file dialog box, which lets you select a new IES lighting file for the light source.
To create a Point light source
  1. Select the Define Light tool.

  2. From the Mode option menu in the Define Light dialog box, choose Create.

    Define Light dialog box

      

  3. From the Type option menu, choose Point Light.
    The Point Light source cell appears, attached to the pointer.

  4. (Optional) If predefined lights are available, use the Name combo box to select a light.

  5. Change settings as required.

  6. Enter a data point to position the light source.

  7. (Optional) If IES data on, enter a data point to define direction of IES point light.

To create a Spot light source
  1. Select the Define Light tool.

  2. From the Mode option menu in the Define Light dialog box, choose Create.

    Define Light dialog box

      

  3. From the Type option menu, choose Spot Light.
    The Spot Light source cell appears, attached to the pointer.

  4. (Optional) If predefined lights are available, use the Name combo box to select a light.

  5. Change settings as required.

  6. Enter a data point to position the light source.

  7. Enter a data point to define the direction and distance of the light source.

    Creating a Spot light source.

      

To create a Distant light source
  1. Select the Define Light tool.

  2. From the Mode option menu in the Define Light dialog box, choose Create.

    Define Light dialog box

      

  3. From the Type option menu, choose Distant Light.
    The Distant Light source cell appears, attached to the pointer.

  4. Change settings as required.

  5. Enter a data point to position the light source.

  6. Enter a data point to define the direction of the light source.

    Creating a Distant light source.

      

To create an Area light source
  1. Select the Define Light tool.

  2. From the Mode option menu in the Define Light dialog box, choose Create.

    Define Light dialog box

      

  3. From the Type option menu, choose Area Light.
    You are prompted to “Identify Element to Convert.”

  4. (Optional) If predefined lights are available, use the Name combo box to select a light.

  5. Identify the element to be converted to an Area light source cell. This is typically the element that represents the light fixture.
    The element highlights, and an arrow indicates the direction of the Area light source.

  6. Define the direction of the Area light source with a data point.
    The light will shine in the direction of the arrow.

  7. Change other settings as required.

  8. Accept the element.
    The element is converted to an Area light source cell.

To create a Sky Opening
  1. Select the Define Light tool.

  2. From the Mode option menu in the Define Light dialog box, choose Create.

    Define Light dialog box.

      

  3. From the Type option menu, choose Sky Opening.
    You are prompted to “Identify element to convert.”

  4. Identify the element to convert to a sky opening.
    The element highlights, and an arrow indicates the direction of the Area light source.

  5. Define the direction of the Area light source with a data point.
    During calculations, only Solar, Sky, and Distant lights that shine through the area of the sky opening, in the direction of the arrow, are considered.

    Optionally, for placing light sources, you can use the key-in light place, which activates the Define Light tool with Mode set to Create.


To change a selected light source's settings
  1. Select the Define Light tool.

  2. If necessary, from the Mode option menu in the Define Light dialog box, choose Modify.

  3. From the Method option menu, choose Edit Light.

  4. Identify the light source. See Identifying light sources.
    Current settings for the identified light source appear in the dialog box. Where multiple light sources are selected, the settings for the last selected light source are displayed.

  5. In the dialog box, adjust the light source's settings.

    6. This is the only Method in which adjusting settings has an immediate effect. All other methods require acceptance of the identified light source with a data point.

    Only those settings that are applicable to the identified light source, as determined by its type, can be changed.

    Optionally, you can use the key-in light edit, which activates the Define Light tool, with Mode set to Modify, and Method set to Edit Light.

To apply the currently displayed settings to a selected light source
  1. Select the Define Light tool.

  2. If necessary, from the Mode option menu, choose Modify.

  3. (Optional) From the Method option menu, choose Edit.

  4. (Optional) Select a light source from the Light List, or scan for an existing light source that has the desired values. See Identifying light sources.

  5. From the Method option menu, choose Apply Value.

  6. (Optional) In the dialog box, adjust the displayed settings as desired.

  7. To apply the settings, double-click the required light in the Light List to complete the task.
    or
    Identify the light source to which to apply the settings (and continue to next step).

  8. In any view, enter a data point to accept the settings.
    The settings are applied to the identified light source.

  9. (Optional) For each additional light source to which to apply the same settings, repeat steps 6-7.

    Steps 3 and 4 let you select an existing light source's settings to apply to another light source. Prior to applying the values, you still can adjust the settings (step 6).

    Optionally, you can use the key-in light apply, which activates the Define Light tool, with Mode set to Modify and Method set to Apply.


To delete a light source
  1. Select the Define Light tool.

  2. If necessary, from the Mode option menu, choose Modify.

  3. From the Method option menu, choose Delete Light.

  4. In the Light List, double-click the required light.
    or
    Identify the light source and accept. See     Identifying light sources.
    An Alert box appears, asking if you are sure that you want to delete the light source.

  5. Click OK.

    6. This Method can be used to delete any type of light source.

    Optionally, you can use the key-in light delete, which activates the Define Light tool, with Mode set to Modify and Method set to Delete.

To move a light source
  1. Select the Define Light tool.

  2. If necessary, from the Mode option menu, choose Modify.

  3. From the Method option menu, choose Move Light.

  4. Double-click the required light in the Light List.
    or
    Identify the light source. See     Identifying light sources.

  5. Enter a data point to reposition the light source.

  6. (For directional light sources only) Enter a data point to reposition the light source's target point.

    7. When moving a directional light source, its location and target points are redefined separately.

    Optionally, you can use the key-in light move, which activates the Define Light tool, with Mode set to Modify and Method set to Move Light.

To reposition a light source's target point, without changing the light source's location
  1. Select the Define Light tool.

  2. If necessary, from the Mode option menu, choose Modify.

  3. From the Method on menu, choose Target Light.

  4. Identify the light source. See Identifying light sources.

  5. Enter a data point to reposition the target point.

    6. This Method applies only to directional light sources.

    Optionally, you can use the key-in light target, which activates the Define Light tool, with Mode set to Modify and Method set to Target Light.

To reposition a light source, without changing its target point
  1. Select the Define Light tool.

  2. If necessary, from the Mode option menu, choose Modify.

  3. From the Method option menu, choose Position Light.

  4. Identify the light source. See “Identifying light sources”.

  5. Enter a data point to reposition the light source.

    6. This Method applies only to directional light sources. This Method is not well suited to Area light sources, as the direction is modified according to the view in which the light source is identified. That is, the Area light source cell is rotated to the orientation of the view being used to define the new location.

    Optionally, you can use the key-in light position, which activates the Define Light tool, with Mode set to Modify and Method set to Position Light.

To move a light source, without changing its relative direction
  1. Select the Define Light tool.

  2. If necessary, from the Mode option menu, choose Modify.

  3. From the Method option menu, choose Dolly Light.

  4. Identify the light source. See Identifying light sources.

  5. Enter a data point to reposition the light source (along with its target point).

    6. When dollying, the light source and its target point move together. That is, the target point remains in the same relative position to the light source. For non-directional light sources, this is identical to Method being set to Move or Position.

    Optionally, you can use the key-in light Dolly, which activates the Define Light tool, with Mode set to Modify and Method set to Dolly Light.

Key-in: LIGHT DEFINE