Surface Edit

The Surface Edit command allows you to modify surface attributes for any selection of Rooms and Objects. Users may quickly select individual surfaces or multiple surfaces collectively, for which they wish to change material properties such as color, texture, meshing, etc.

  1. From the Modify menu, choose Surface Edit, or from the Rooms/Objects Toolkit select . Click the arrow adjacent to the Surface Edit button to view the secondary menu with additional selection options.
  2. Many selection options are available to assist you in selecting only the entities that you wish to edit. You may choose from the following parameters:
  1. In the Surface Edit dialog, you may use the Display Options button below the image to change its appearance, such as showing it as outlines only or filled in, and changing the background color. You may use the interactive navigation buttons to view the object from different angles. (Additional information below)
  2. Use the navigate at the top-left in the dialog to change the highlight to the surface or group of surfaces you wish to edit. Tagging surfaces allows you to quickly select multiple surfaces based on inherent relationships in AGi32 entities.
  3. The Surface and Advanced Surface Properties sections provide access to all of the available options. More discussion of each attribute is discussed below. As each modification is applied, the Session History section, in the lower left corner of the dialog, provides continuous feedback on the changes made.
  4. Click OK. The surfaces will be changed per your specifications. To see a preview of the changes in most cases, view the Shaded surfaces (available from the Display Properties dialog) in Render Mode.

 

Navigation, Tag and View Control Icons

Icon

Command

Keyboard Shortcut

Comments

Move to Previous Surface

F9

Navigates to previous surface in selected room or object.

Move to Next Surface

F10

Navigates to next surface in selected room or object.

Move to Previous Component

F11

Navigates to the first surface in the previous component in the selected object. Objects only contain multiple components if they are composed of grouped objects (Library Objects) or multiple layers (imported 3D Objects).

To navigate within the surfaces of a component, use the Move to Next/Previous Surface commands.

Move to Next Component

F12

Navigates to the first surface in the next component in the selected object. Objects only contain multiple components if they are composed of grouped objects (Library Objects) or multiple layers (imported 3D Objects).

To navigate within the surfaces of a component, use the Move to Next/Previous Surface commands.

Tag Current Surface

F8

Selects the current surface for surface modifications. Surfaces only need to be tagged if you want to make modifications to more than one surface.

Tag Ceiling, Top or Roof

Ctrl+E

Selects all surfaces that were created as ceilings (in Rooms) or tops (in Objects) for surface modifications. Surfaces only need to be tagged if you want to make modifications to more than one surface.

Tag Walls or Sides

Ctrl+W

Selects all surfaces that were created as walls (in Rooms), or sides (in Objects) for surface modifications. Surfaces only need to be tagged if you want to make modifications to more than one surface.

Tag Floor or Bottom

Ctrl+F

Selects all surfaces that were created as floors (in Rooms), or bottoms (in Objects) for surface modifications. Surfaces only need to be tagged if you want to make modifications to more than one surface.

Tag Object Component

Ctrl+O

Selects all surfaces in the current Object component for surface modifications. Surfaces only need to be tagged if you want to make modifications to more than one surface.

Tag All Surfaces

Ctrl+A

Selects all surfaces for surface modifications. Surfaces only need to be tagged if you want to make modifications to more than one surface.

Tag Surfaces With Same Color/Reflectance as Current Surface

Ctrl+S

Selects all surfaces with the same Color and Reflectance attribute as the current selected surface. Surfaces only need to be tagged if you want to make modifications to more than one surface.

Tag Surfaces With Same Surface Type as Current Surface

Ctrl+Y

Selects all surfaces with the same Surface Type (e.g. Single Sided) as the current selected surface. Surfaces only need to be tagged if you want to make modifications to more than one surface.

Remove All Tags

Ctrl+R

Deselects all selected surfaces. Necessary when you wish to apply alternate surface modifications to different surfaces. Note: Surfaces remain tagged, even when additional surfaces are tagged, until Tags are individually or collectively removed.

Front View

 

Displays a Front (South) Elevation View of Object or Room in graphic display.

Back

 

Displays a Back (North) Elevation View of Object or Room in graphic display.

Left

 

Displays a Left (West) Elevation View of Object or Room in graphic display.

Right

 

Displays a Right (East) Elevation View of Object or Room in graphic display.

Top

 

Displays a Top Plan View of Object or Room in graphic display.

Bottom

 

Displays a Bottom Plan View of Object or Room in graphic display.
Clip   Cuts away the front plane of the image continuously to reveal the objects within and beyond. The size of the image does not increase or decrease. This command is very useful when viewing an image with exterior and interior components (e.g., interior and site lighting).
Dolly   Moves the observer and the focus point in and out of the model along a straight line. Depending on the view direction, from the observer’s point of view, this feature allows you to “walk” into and out of the space.
Orbit   Moves the observer around the model while maintaining the same focus point. Imagine that you are a spaceship orbiting the earth, always looking at the center of the earth.
Pan   Moves the observer and focus point relative to a fixed model position. Imagine that you are looking straight ahead and moving laterally left/right or up/down. The image will move opposite to the panning direction.
Rotate   Allows the observer to look left or right and up or down from a fixed position. Use this command when you are in a space and want to look at different surfaces without changing your position. A panorama view is obtained by moving constantly to the left or right.
Walk   Combines the Dolly, Pan and Rotate commands into one movement. Dragging the mouse up/down moves the observer forward and backward. Dragging the mouse left/right, rotates the observer view position left and right. Using the Shift and Ctrl keys in conjunction with dragging or the arrow keys invokes the Rotate and Pan commands as well.
Zoom   Similar to the Zoom In and Zoom Out commands in AGi32’s Model Mode, with the difference being that the image size is continuously increased or decreased as the mouse is held down and dragged.

 

Display Options

Clicking on the Display Options button below the image opens a list of ways that the image appearance may be modified. For example, you may select to keep outlines visible and surfaces filled in, but not show text or drawing entities associated with this Object or Room. These selections apply to the image seen in the Surface Edit dialog only. By default, all options are selected, with the background color available for modification.

 

Additional Dialog Options - In order of appearance in Surface Edit dialog

Entity Selection

The Entity pull-down menu contains a list of all selected entities. By default, All entities are selected and available for modification. Selection proceeds by navigating through each surface of each entity in alphabetical order as they are presented in the Entity list. Individual Entity selection is also available as an alternative. This is handy if you graphically selected multiple entities in close proximity, but are only interested in modifying a partial or singular Entity from the group. For example, if you selected both a room opening and planar object insert (e.g. a window) and wish to edit only the window, you could select the Object by name and edit it directly without having to navigate through the room surfaces first.

Dialog Settings

This dialog section controls the display options for surfaces. This section is hidden by default.

Tag Surface Color - Indicates the line color of tagged surfaces. Default color is yellow, color may be changed by user.

Current Surface Color - Indicates the line color of current selected surface. Default color is cyan, color may be changed by user.

Removed Surface Color - Indicates the line color of removed surfaces. Default color is Black, color may be changed by user.

Normal Vector Color - Indicates the line color of the Normal Vector. Default color is black, color may be changed by user.

Normal Vector Length - Indicates the Normal Vector length in current units - feet or meters (e.g. 4 feet). The Normal Vector indicates the Normal side of the selected surface by default. Vector Length is automatically calculated from 15% of maximum entity extents in X or Y (whichever is largest), may be changed by user.

Axis Color - Indicates the line color of Coordinate Axis. Default color is red, color may be changed by user. Coordinate Axis is displayed in centroid of selected entity.

Axis Size - Indicates the Axis length in current units - feet or meters (e.g. 4 feet). Axis Length is automatically calculated from 15% of maximum entity extents in X or Y (whichever is largest), may be changed by user.

 

General

This dialog section indicates which entity and surface is currently selected.

Entity Type - Indicates the type of Entity selected - Room or Object. Text box is only displayed for informational purposes, not changeable by user.

Entity Label - Indicates the Label of the selected Entity - originally assigned by user when entity was created. Text box is only displayed for informational purposes, not changeable in this dialog by user.

Component Label - Indicates the Label of the current component in the selected Entity - originally assigned by user when entity was created. Component Label only contains information if Objects are selected.

 

Surfaces

The following Surface properties can be applied to any of the surfaces of your objects (except for number which is assigned when the room or object is created).

Number - Indicates the surface number of the currently selected surface. You may also scroll through the surfaces with the Up and Down arrows provided here or type in a number manually.

 

Tag - Indicates if the surface is tagged or not. You may manually change the Tag associated with the current surface by changing the Tag text box from Off to On and vice versa.

 

Label - Indicates the surface Label (Floor, Bottom, Walls, Sides, Ceiling or Top) of the selected surface.

 

Removed- Indicates whether the surface is considered in the calculations. Surfaces may be removed to create complex spaces from composite models, by making a surface invisible. Removed surfaces may be added back to the environment by changing the removed parameter back to No.

Type

The Surface Type menu provides many specific surfaces used for various calculation purposes in AGi32. Some surfaces types are available purely for optimization and visualization purposes in AGi32. For example, Single Sided surfaces are more efficient for swift calculations than Double Sided surfaces. They also allow the user to look within the space from the "back" side, without having to move within the space in render mode. Rooms are created from Single Sided surfaces (with the Normal facing into the room for each surface) primarily for these reasons. Other surface types are available for specific calculation purposes, such as Daylighting or interreflected roadway calculations (e.g., Tunnel Lighting). A list of each surface type is provided below.

Daylight - Surfaces imported in to or created within AGi32 must be assign appropriate surface types (and attributes) specifically for daylighting analysis. Exterior surfaces considered in daylighting computations are handled differently, and separately, from other surfaces. These surfaces must have the Daylight Exterior attribute (set to Yes) in the Daylight Exterior property cell. Surfaces associated with windows or openings (we call these Daylight Transition surfaces) that bring daylight into interior spaces must be assigned one of the Daylight Transition surface types (numbers 20, 21 & 22). (Note: 14-Glass is not appropriate for windows and skylights.)

Roadway - Surfaces to be used in conjunction with the Roadway Calculation grids (luminance, veiling luminance, etc.) must be allocated as Roadway Pavement or Roadway Contributors. Roadway surfaces should be specified as Roadway Pavement Single Sided (Direct Flux Only). Surfaces that obstruct and/or reflect light onto pavement should be specified as Roadway Contributor Single Sided.

Once the model is created, use the Surface Edit command to change the surface types for any relevant surfaces according to the following table:

Surface Type

Comments

10- Single Sided

Receives and reflects Direct and Indirect daylight (after it passes through Daylight Transition surfaces) and electric light.

Surfaces are single sided - surface normal must face target direction. This is the default for Rooms - surface normals face inwards.

Surface type is more efficient than Surface 11 (less surfaces to consider).

This surface type cannot be made transparent or translucent.

11- Double Sided

Receives and reflects Direct and Indirect daylight (after it passes through Daylight Transition surfaces) and electric light.

Surfaces are double sided (default for Objects).

Surfaces will transmit light diffusely if Transmittance is >0.

Color or Texture may be applied.

14- Glass

Surface transmits both direct and interreflected electric light and daylight diffusely. This surface type appears transparent in Render Mode and Raytrace images. Note: Daylight must pass through a Daylight Transition surface before it can pass through Glass.

In Raytrace images, transmittance is based on incident angle (surface behaves as a Fresnel transmitter).

Transparency and/or Color can be set. Textures cannot be applied.

Surface is double sided. More information on Glass Concepts

20- Daylight Transition Glass (transparent)

Daylight Transition surfaces are required to bring daylight into an interior environment (used to model fenestration and skylights). Allows transparency values between 0-100%: 0 - Opaque, 100 - Clear). Surface may be assigned color tint.

This surface type appears transparent in Render Mode and Raytrace images.

Surface attenuates light based on Fresnel Transmittance and Reflectance methods. Predefined glazing Visible Transmittance (VT) values are available.

21- Daylight Transition Glass (diffuse)

Daylight Transition surfaces are required to bring daylight into an interior environment (used to model fenestration and skylights). Allows Transmittance values between 0-100%: 0 - Opaque, 100 - Clear). Surface may be assigned color tint.

Surface transmits daylight into interior in lambertian manner (perfectly diffuse).

22- Daylight Transition Opening

Daylight transition surfaces are required to bring daylight into an interior environment. Surface Type is perfectly clear (100% Transparency); all light entering environment is white.

Surface Type does not reflect light.

40- Roadway Pavement Single Sided (Direct Flux Only)

Receives Direct Electric Lighting. This surface type receives only direct light from electric lighting sources; daylighting is disregarded.

Surfaces are single sided - surface normal must face upward.

41- Roadway Contributor Single Sided

Receives and reflects direct and indirect electric lighting. Daylighting is not considered.

Surfaces are single sided - surface normal must face towards Roadway Pavement.

 

Daylight Exterior - Indicates the surface receives direct and indirect daylight and is located on the exterior side of any Daylight  Transition surfaces -- those directly visible to sun and sky. This option is only necessary when daylighting calculations are performed. For electric lighting only computations, it does not matter whether the application is exterior or interior, and this attribute is disregarded.

 

Color - Indicates the surface color of the selected surface - both a thumbnail and hexadecimal color value are displayed. To change the Surface Color, click in the Color text box, then click on the pull-down arrow icon (or press F4). Depending on the associated surface type, an appropriate Color specification dialog will appear.

Surface Type

Associated Dialog

Single or Double Sided

Color/Reflectance selector

Glass

Color/Transparency Selector

Daylight Transition Glass (Transparent)

Color/Transparency Selector

Daylight Transition Glass (Diffuse)

Color/Reflectance selector

Daylight Transition Opening

Not Available

Roadway Pavement Single Sided

Not Available - Based on associated R-table selected in Roadway Luminance calculation grid dialog.

Roadway Contributor Single Sided

Color/Reflectance selector

 

Reflect - Indicates the Reflectance of the selected surface. The current or tagged surface reflectances may be changed in this text box without having to access the Color/Reflectance dialog. If the specified reflectance exceeds the maximum allowable reflectance for the currently selected color, a message is displayed indicating the maximum allowable reflectance. When the Reflectance is changed, the associated Color is recalculated and redisplayed.

Texture - Indicates whether a texture is applied to the selected surfaces. The text box displays the following options:

Display

Comments

None

No texture is specified

Texture Name

Specified texture name is displayed

Textures are graphic images that may be applied to surfaces to make them appear more realistic. The average reflectance and color of the texture are calculated and used instead of the surface's original color in the radiosity calculations.

AGi32 comes with a selection of assorted textures that may be applied to any surface. You may also obtain textures from many other sources, including free texture sites online and commercial texture collections. You may even use your digital camera to obtain them directly. Click here to read about texture tips.

Assign a texture to the selected surface by clicking in the Texture cell, then clicking on the ellipsis (dots) icon, or press F4. The Select Texture dialog will appear, allowing you to choose a texture from the Textures database. Alternatively, you may Browse for a texture anywhere on your system or assign a texture already in use on another surface in the job file. Once the desired texture is selected, you can specify how the texture should be applied to the surface. Textures may be stretched across the entire surface, applied in a grid pattern, or assigned a fixed size (representing real dimensions) and tiled on the surface accordingly. In addition, you may elect to rotate the texture on the surface.

To delete a texture from the surface, click in the Texture cell and hit the Delete key on your keyboard. When a texture is deleted from a surface, its calculated overall color and reflectance are used as the current color and reflectance.

Transmittance - Indicates whether Transmittance is assigned to the selected surfaces. Transmittance is available for Double Sided  and Daylight Transition Glass (diffuse) surface types. In addition to reflectance, surfaces can have an optional diffuse Transmittance value, allowing a percentage of light to pass through the object in a lambertian manner. The specified transmittance value is entered as a decimal value (e.g., 20% Transmittance is specified as 0.2).

This transmittance value is mathematically related to the color of the object, thus limiting the response acceptable in the Transmittance cell. AGi32 automatically computes the maximum transmittance possible for the surface based on the color/reflectance selected. If you enter a transmittance value greater than the maximum allowed, AGi32 will display a message specifying the maximum allowable Transmittance value.

This is not to be confused with the Transparency property used to model transparent Daylight Transition Glass (e.g., clear windows). Surfaces with transmittance do not appear transparent in the AGi32 rendering.

Transparency - Indicates whether Transparency is assigned to the selected surfaces. Transparency is available for the following surfaces types: Daylight Transition Glass (transparent) and Glass. This allows you to consider transparent surfaces in order to model the transmission of daylight through clear glass or plastic.

The transparency value may be entered manually (specify a value between 0.01 and 1), or you may select  the pull-down arrow icon (alternately press F4) to view a list of common glazing configurations with their associated transparency value. Note: To obtain transparency values from other commercial glazing products or systems, look for the Visible Transmittance value (VT). This value corresponds to the Transparency value in AGi32.

The transmission of light through transparent materials is dependent on the angle of incidence. When light strikes a surface in a perpendicular manner, nearly all of the light is transmitted (approximately 96%). However, when light strikes the surface at a glancing angle, a very large percentage of the light may be reflected. AGi32 is able to accurately consider the transmission of light through a transparent surface. It is not, however, able to consider the reflection of light off of the transparent surface, except in Ray Tracing.

AGi32 is capable of assigning a color to a transparent surface in order to model tinted glass. Light passing through the surface will be assigned this color along with the appropriate depreciation in the amount of light that can pass through. The tinted surface is visible in the rendering.

Facts about Transparent surfaces in AGi32

Transparent surfaces -vs- Transmittance surfaces

Both Transparent and Transmittance surfaces can consider the transmittance of light from one side of the surface to the other. However, the way in which they do so is completely different.

Creation of a Daylight Transition surface

Any surface can be assigned as a Daylight Transition Glass (transparent or diffuse or Opening) surface type, including surfaces associated with Rooms or Objects. The surface Normals must face into the desired interior space to properly direct the daylight into the space.

When an opening is cut into a Room or Object, an option to create a Planar Object as an insert is offered. Select Yes to create a Planar Object with the same boundary as the opening. The Insert is assigned the following attributes by default:

Road Surface - Indicates the R-Table and Q0  value for a roadway pavement surface. (Only applies to surface type 41 - Roadway Pavement Single-Sided (Direct Flux Only.)

To change the R-Table and/or Q0 value, click in the field and then click on the ... button to open the Roadway Surface dialog. You may select from one of several R-Table types. Selecting an R-Table will also cause the Q0 value to change, according to the R-Table selected. A new value may also be entered in the Q0 field without changing the R-Table selection.

Important: This function enables the user to specify the surface type for multiple surfaces independently of the calculation grid, which allows the user to consider more than one roadway surface type in an inter-reflective environment. However, this function must be used with caution! There is no association between roadway surfaces and roadway calculation grids. It is up to the user to place the proper calculation grid on the roadway surface; i.e., specify the same R-Table and Q0 value in the Roadway Calculation Grid dialog as here.

 

Advanced Surface Properties

This section provides additional surface parameters for ray tracing applications as well as advanced surface modifications.

Specularity (Ray Trace Only) - Indicates the specularity (shininess) of the selected surfaces. By default, the value is 0 (no specularity); it may be increased up to 1 (100%, mirror reflection). The value may be entered directly or specified in the Specularity dialog. To use the Specularity dialog, click in the Specularity text box and then click on the ellipsis (dots) icon (or press F4).

Surfaces may be made to look shiny by adding a Specularity value to their surface properties. This attribute is only visible in Ray Trace images and does not affect the numeric and radiosity calculations is any way. It is simply a post-process effect that is added to the surface when Ray Trace images are created.

Glossiness (Ray Trace Only) - Indicates the apparent smoothness (low gloss or high gloss) of the selected specular surfaces. The range of Glossiness is 0.0001 (essentially diffuse) to 1.00 (perfectly specular). The default value is 0 - no glossiness applied. A value of 0.10 is recommended to provide a realistic appearing low gloss finish to surfaces for most applications. The value is entered directly.

Glossiness may be added to any Specular surface, including Transition surfaces and Glass. This attribute is only visible in Ray Trace images and is not used in the numeric and radiosity calculations is any way. It is simply a post process effect that is added to the surface when Ray Trace images are created.

Assigning a Glossiness value will increase the Ray Trace calculation time.

Color Bleed - Indicates the Color Bleed scale of the selected surfaces. By default, the value is 1 (100%, full Color Bleed); it may be decreased to 0 (0%, no Color Bleed). The value may be entered directly or specified in the Color Bleed dialog. To use the Color Bleed dialog, click in the Color Bleed text box and then click on the ellipsis (dots) icon (or press F4).

Color Bleed is a real, physically observable phenomenon that occurs when strongly saturated colors are reflected to adjacent surfaces. Take a brightly colored surface (like red construction paper) and hold it horizontally next to any white wall. You'll observe a red tint on the wall from the red light reflected off the paper; the red color is the color bleed.

Computer generated environments with strong colors (e.g., a bright green carpet) tend to produce a color cast in the rendered environments. In real life, our eyes and brain compensate for the color cast and we would see the walls and ceiling as white. Color photographs and video displays do not compensate for the color cast automatically, and the rendered environment can appear unrealistic in this regard.

The Color Bleed scale simulates human color vision adaptation. It is applied on an individual surface basis and should be applied to surfaces with strongly saturated color.

Mesh Level - Indicates the Mesh Level of the selected surfaces. Mesh Level may be modified as necessary: increased  to improve the surface's response to its environment, or decreased to improve calculation times (opposite considerations). The Mesh Level value may be entered directly (e.g., 4.1), or specified in the Mesh Level dialog. To use the Mesh Level dialog, click in the Mesh Level text box and then click on the ellipsis (dots) icon (or Press F4).

The Mesh Level syntax is as follows: <Patch level>.<Element Level>, per the Radiosity process used in AGi32. Increasing the Patch Level and/or Element Level will increase your calculation times. Note: Increasing the Patch Level, automatically increases the number of elements in each surface (even without additionally increasing the Element Level).

Transition Surfaces: Daylight Transition Glass (transparent) and Daylight Transition Opening surface types only use the Patch Level specification and are originally meshed based on the "Initial Meshing -Transition Surface Types" settings in the Advanced System Settings dialog. These surface types do not include Elements (all light hitting the surfaces from other Patches or direct electric sources is absorbed). Diffuse Daylight Transition Glass (diffuse) surface types are composed of Patches and Elements and are originally meshed based on the "Initial Meshing -General Surface Types" settings in the Advanced System Settings dialog.

Note: Changing the Mesh Level  manually in the Surface Edit dialog requires a thorough knowledge of how patches and elements are used in the radiosity calculations. Changing these values inappropriately can lead to unreasonably long calculations times (at best) or to inaccurate simulations (at worst).

If you are unfamiliar with AGi32's radiosity process and need to refine your mesh, consider using Adaptive Subdivision instead.

Luminance- Indicates the absolute Luminance of surfaces. By default, this value is zero, meaning that a surface does not self "emit"; it is only illuminated by the light it receives from other surfaces, luminaires, or daylight.

Surfaces assigned a Luminance value are used to emulate virtual luminous surfaces - such as cold cathode, neon, computer monitors, photo-luminous surfaces and more.

Luminance is only available for Single and Double Sided Surface types, and is specified as a value between 1 and 30000 cd / m2. This specification allows you to set an absolute Luminance of the surface as a lambertian emitter.

Double sided surfaces assigned a Luminance value may also be assigned a Transmittance value.

The surface Luminance is used in the calculation results as well as in the rendered images.

Luminance is always specified in cd/sq.m, regardless of your current display units. A Luminance Calculator is available allowing you to convert the following units to cd/sq.m: Lumens/Sq.Ft, Lumens/Sq.M, Lumens/Linear Ft, and Lumens/Linear M.

Luminance Color - Indicates the emitted surface color of the selected surface; both a thumbnail and hexadecimal color value are displayed. By default, Luminance color is equal to Reflectance color; however, they can be different. To change the Luminance Color, click in the Color text box and then click on the pull-down arrow icon (or Press F4).The Color / SRE dialog will appear.

Direct Flux Only - This attribute indicates that the surface receives, reflects, and obstructsdirect daylighting and/or electric lighting only (no interreflected light). In other words, DFO surfaces totally ignore reflected light; they do not receive, reflect or block reflected light. This attribute is useful for surfaces that receive little or no reflected light, to speed up radiosity calculation process. For example, a parking lot surface in a project with few other reflective surfaces (e.g., objects) may benefit from this optimization.

When secondary sources are enabled, DFO (Direct Flux Only) surfaces will receive one additional interreflected "bounce" due to these secondary sources.

Session History

The Session History section indicates surface count as well as a running tabulation of the calculation options applied in this session.

Total Surfaces - The total surface count for the selected Object and/or Room entities.

Number Selected/Tagged - The total number of surfaces currently selected and tagged. Any modifications made are applied to all selected surfaces. Hint: If you wish to make individual changes to certain surfaces, click Remove All Tags and then only select the surfaces you wish to apply these changes to.

Number of Surfaces Changed - Indicates the number of surfaces that the last modification was applied to.