---
description: wxGUI 3D View Mode
index: wxGUI
keywords: [display, GUI, visualization, graphics, raster, vector, raster3d]
---

# wxGUI 3D View Mode

## DESCRIPTION

**wxNviz** is a *[wxGUI](wxGUI.md)* **3D view mode** which allows users
to realistically render multiple *surfaces* (2D raster maps) in a 3D
space, optionally using thematic coloring, draping 2D *vector* data or
different 2D raster data over the surfaces, displaying 3D vector data in
the space, and visualization of *3D rasters*.

To start the wxGUI 3D view mode, choose '3D view' from the map toolbar.
You can switch between 2D and 3D view. The region in 3D view is updated
according to displayed region in 2D view.

wxNviz is emphasized on the ease and speed of viewer positioning and
provided flexibility for using a wide range of data. A low resolution
surface or wire grid (optional) provides real-time viewer positioning
capabilities. Coarse and fine resolution controls allow the user to
further refine drawing speed and detail as needed. Continuous scaling of
elevation provides the ability to use various data types for the
vertical dimension.

For each session of wxNviz, you might want the same set of 2D/3D raster
and vector data, view parameters, or other attributes. For consistency
between sessions, you can store this information in the GRASS
*workspace* file (gxw). Workspace contains information to restore
"state" of the system in 2D and if wxNviz is enabled also in the 3D
display mode.

## 3D View Toolbar

![toolbar](wxGUI_nviz_toolbar.jpg)

![icon](icons/script-save.png)  *Generate command for m.nviz.image*:
Generate command for m.nviz.image based on current state.

![icon](icons/settings.png)  *Show 3D view mode settings*:
Show dialog with settings for wxGUI 3D view mode. The user settings can
be stored in wxGUI settings file.

![icon](icons/help.png)  *Show help*:
Show this help.

## 3D View Layer Manager Toolbox

The 3D view toolbox is integrated in the Layer Manager. The toolbox has
several tabs:

- **View** for view controlling,
- **Data** for data properties,
- **Appearance** for appearance settings (lighting, fringes, ...).
- **Analysis** for various data analyses (only cutting planes so far).
- **Animation** for creating simple animations.

### View

You can use this panel to set the *position, direction, and perspective*
of the view. The position box shows a puck with a direction line
pointing to the center. The direction line indicates the look direction
(azimuth). You click and drag the puck to change the current eye
position. Another way to change eye position is to press the buttons
around the position box representing cardinal and ordinal directions.

There are four other buttons for view control in the bottom of this
panel (following label *Look:*):

- *here* requires you to click on Map Display Window to determine the
  point to look at.
- *center* changes the point you are looking at to the center.
- *top* moves the current eye position above the map center.
- *reset* returns all current view settings to their default values.

![toolbox](wxGUI_nviz_tools_view.jpg)

You can adjust the viewer's height above the scene, perspective and
twist value to rotate the scene about the horizontal axis. An angle of 0
is flat. The scene rotates between -90 and 90 degrees.

You can also adjusts the vertical exaggeration of the surface. As an
example, if the easting and northing are in meters and the elevation in
feet, a vertical exaggeration of 0.305 would produce a true
(unexaggerated) surface.

View parameters can be controlled by sliders or edited directly in the
text boxes. It is possible to enter values which are out of slider's
range (and it will then adjust to the new range).

#### Fly-through mode

View can be changed in fly-through mode (can be activated in Map Display
toolbar), which enables to change the view smoothly and therefore it is
suitable for creating animation (see below). To start flying, press left
mouse button and hold it down to continue flying. Flight direction is
controlled by mouse cursor position on screen. Flight speed can be
increased/decreased stepwise by keys PageUp/PageDown, Home/End or
Up/Down arrows. Speed is increased multiple times while Shift key is
held down. Holding down Ctrl key switches flight mode in the way that
position of viewpoint is changed (not the direction).

### Data properties

This tab controls the parameters related to map layers. It consists of
four collapsible panels - *Surface*, *Constant surface*, *Vector* and
*3D raster*.

#### Surface

Each active raster map layer from the current layer tree is displayed as
surface in the 3D space. This panel controls how loaded surfaces are
drawn. To change parameters of a surface, it must be selected in the
very top part of the panel.

The top half of the panel has drawing style options. Surface can be
drawn as a wire mesh or using filled polygons (most realistic). You can
set draw **mode** to *coarse* (fast display mode), *fine* (draws surface
as filled polygons with fine resolution) or *both* (which combines
coarse and fine mode). Additionally set coarse **style** to *wire* to
draw the surface as wire mesh (you can also choose color of the wire) or
*surface* to draw the surface using coarse resolution filled polygons.
This is a low resolution version of the polygon surface style. E.g.
surface is drawn as a wire mesh if you set **mode** to *coarse* and
**style** to *wire*. Note that it differs from the mesh drawn in fast
display mode because hidden lines are not drawn. To draw the surface
using filled polygons, but with wire mesh draped over it, choose
**mode** *both* and **style** *wire*. Beside mode and style you can also
choose style of **shading** used for the surface. *Gouraud* style draws
the surfaces with a smooth shading to blend individual cell colors
together, *flat* draws the surfaces with flat shading with one color for
every two cells. The surface appears faceted.

To set given draw settings for all loaded surfaces press button "Set to
all".

The bottom half of the panel has options to set, unset or modify
attributes of the current surface. Separate raster data or constants can
be used for various attributes of the surface:

- **color** - raster map or constant color to drape over the current
  surface. This option is useful for draping imagery such as aerial
  photography over a DEM.
- **mask** - raster map that controls the areas displayed from the
  current surface.
- **transparency** - raster map or constant value that controls the
  transparency of the current surface. The default is completely opaque.
  Range from 0 (opaque) to 100 (transparent).
- **shininess** - raster map or constant value that controls the
  shininess (reflectivity) of the current surface. Range from 0 to 100.

In the very bottom part of the panel position of surface can be set. To
move the surface right (looking from the south) choose *X* axis and set
some positive value. To reset the surface position press *Reset* button.

![wxGUI nviz tools surface](wxGUI_nviz_tools_surface.jpg)

#### Constant surface

It is possible to add constant surface and set its properties like fine
resolution, value (height), color and transparency. It behaves similarly
to surface but it has less options.

#### Vector

2D vector data can be draped on the selected surfaces with various
markers to represent point data; you can use attribute of vector
features to determine size, color, shape of glyph. 3D vector data
including volumes (closed group of faces with one kernel inside) is also
supported. This panel controls how loaded 2D or 3D vector data are
drawn.

You can define the width (in pixels) of the line features, the color
used for lines or point markers.

If vector map is 2D you can display vector features as flat at a
specified elevation or drape it over a surface(s) at a specified height.
Use the height control to set the flat elevation or the drape height
above the surface(s). In case of multiple surfaces it is possible to
specify which surfaces is the vector map draped over.

For display purposes, it is better to set the height slightly above the
surface. If the height is set at zero, portions of the vector may
disappear into the surface(s).

For 2D/3D vector points you can also set the size of the markers.
Currently are implemented these markers:

- **x** sets the current points markers to a 2D "X",
- **sphere** - solid 3D sphere,
- **diamond** - solid 3D diamond,
- **cube** - solid 3D cube,
- **box** - hollow 3D cube,
- **gyroscope** - hollow 3D sphere,
- **asterisk** - 3D line-star.

Thematic mapping can be used to determine marker color and size (and
line color and width).

![wxGUI nviz tools vector](wxGUI_nviz_tools_vector.jpg)

#### 3D rasters

3D raster maps (volumes, voxel models) can be displayed either as
isosurfaces or slices. Similarly to surface panel you can define draw
**shading** - *gouraud* (draws the 3D rasters with a smooth shading to
blend individual cell colors together) and *flat* (draws the 3D rasters
with flat shading with one color for every two cells. The 3D raster
appears faceted). As mentioned above currently are supported two
visualization modes:

- **isosurface** - the levels of values for drawing the 3D raster(s) as
  isosurfaces,
- and **slice** - drawing the 3D raster as cross-sections.

The middle part of the panel has controls to add, delete, move up/down
selected isosurface or slice. The bottom part differs for isosurface and
slice. When choosing an isosurface, this part the of panel has options
to set, unset or modify attributes of the current isosurface. Various
attributes of the isosurface can be defined, similarly to surface
attributes:

- **isosurface value** - reference isosurface value (height in map
  units).
- **color** - raster map or constant color to drape over the current 3D
  raster.
- **mask** - raster map that controls the areas displayed from the
  current 3D raster.
- **transparency** - raster map or constant value that controls the
  transparency of the current 3D raster. The default is completely
  opaque. Range from 0 (opaque) to 100 (transparent).
- **shininess** - raster map or constant value that controls the
  shininess (reflectivity) of the current 3D raster. Range from 0 to
  100.

In case of 3D raster slice the bottom part of the panel controls the
slice attributes (which axis is slice parallel to, position of slice
edges, transparency). Press button *Reset* to reset slice position
attributes.

3D rasters can be moved the same way like surfaces do.

![toolbox](wxGUI_nviz_tools_volume.jpg)

### Analysis

*Analysis* tab contains *Cutting planes* panel.

#### Cutting planes

Cutting planes allow cutting surfaces along a plane. You can switch
between six planes; to disable cutting planes switch to *None*.
Initially the plane is vertical, you can change it to horizontal by
setting *tilt* 90 degrees. The *X* and *Y* values specify the rotation
center of plane. You can see better what *X* and *Y* do when changing
*rotation*. The *Height* parameter applies only when changing *tilt*
concurrently. Press the *Reset* button to reset the current cutting
plane.

In case of multiple surfaces you can visualize the cutting plane by
*Shading*. Shading is visible only when more than one surface is loaded
and these surfaces must have the same fine resolution set.

### Appearance

Appearance tab consists of three collapsible panels:

- *Lighting* for adjusting light source
- *Fringe* for drawing fringes
- *Decorations* to display north arrow and scale bar

The *lighting* panel enables to change the position of light source,
light color, brightness and ambient. Light position is controlled
similarly to eye position. If option *Show light model* is enabled light
model is displayed to visualize the light settings.

![toolbox](wxGUI_nviz_tools_light.jpg)

The *Fringe* panel allows you to draw fringes in different directions
(North & East, South & East, South & West, North & West). It is possible
to set the fringe color and height of the bottom edge.

The *Decorations* panel enables to display north arrow and simple scale
bar. North arrow and scale bar length is determined in map units. You
can display more than one scale bar.

### Animation

Animation panel enables to create a simple animation as a sequence of
images. Press 'Record' button and start changing the view. Views are
recorded in given interval (FPS - Frames Per Second). After recording,
the animation can be replayed. To save the animation, fill in the
directory and file prefix, choose image format (PPM or TIF) and then
press 'Save'. Now wait until the last image is generated. It is
recommended to record animations using fly-through mode to achieve
smooth motion.

## Settings

This panel has controls which allows user to set default surface, vector
and 3D raster data attributes. You can also modify default view
parameters, or to set the background color of the Map Display Window
(the default color is white).

## To be implemented

- Labels, decoration, etc. (Implemented, but not fully functional)
- Surface - mask by zero/elevation, more interactive positioning
- Vector points - implement display mode flat/surface for 2D points
- ...

## NOTE

Please note that with wxGTK port of wxPython (Linux systems), a problem
might appear during wxNviz initialization (nothing is rendered at all)
or when rendering vectors (bad order of rendering surfaces and vectors).
If you encounter such problems, try to change a depth buffer number in
*wxGUI Settings \> Preferences \> Map Display \> Advanced* (possible
numbers are 0, 16, 24, 32). It is currently not possible to
automatically determine the right number which is working for your
computer.

## SEE ALSO

*[wxGUI](wxGUI.md), [wxGUI components](wxGUI.components.md)*

See also [wiki](https://grasswiki.osgeo.org/wiki/WxNVIZ) page
(especially various [video
tutorials](https://grasswiki.osgeo.org/wiki/WxNVIZ#Video_tutorials)).

Command-line module *[m.nviz.image](m.nviz.image.md)*.

## AUTHORS

### The wxNviz GUI

[Martin Landa](http://geo.fsv.cvut.cz/gwiki/Landa), [Google Summer of
Code 2008](https://grasswiki.osgeo.org/wiki/WxNviz_GSoC_2008) (mentor:
Michael Barton) and
[2010](https://grasswiki.osgeo.org/wiki/WxNviz_GSoC_2010) (mentor:
Helena Mitasova)  
Anna Kratochvilova, [Google Summer of Code
2011](https://grasswiki.osgeo.org/wiki/WxNviz_GSoC_2011) (mentor: Martin
Landa)

### The OGSF library and NVIZ engine

NVIZ (GRASS's *n*-dimensional visualization suite) was written by Bill
Brown, Terry Baker, Mark Astley, and David Gerdes, U.S. Army Corps of
Engineers Research Laboratories, Champaign, Illinois and UI GMS
Laboratory, Urbana, IL in the early 1990s.

Original documentation was written by Terry Baker (spring 1995), and
updated by Mark Astley, based on a document written by Bill Brown.
Additional design help and funding in the early 1990s by Helena Mitasova
(CERL). Tcl/Tk support added by Terry Baker. Ported to Linux by Jaro
Hofierka and others. Conversion from SGI IRIS GL code to OpenGL by
Justin Hickey. Further program and documentation (2004) updates by Bob
Covill, Tekmap Consulting. 3D volume support by Tomas Paudits with
supervision from Jaro Hofierka and Helena Mitasova. Fly-through mode,
thematic site attributes, and picking by Massimo Cuomo (ACS) with
updates by Michael Barton. GRASS 6 vector support by Radim Blazek.
Additional updates by Markus Neteler, Martin Landa, Glynn Clements, and
Hamish Bowman.

NVIZ evolved from the earlier GRASS program *SG3d* written for Silicon
Graphics IRIS GL by Bill Brown and Dave Gerdes at USA CERL, 1990-1995
and from the NVIZ Motif version written by Bill Brown with contributions
by Terrance McGhee.

## SOURCE CODE

Available at: [wxGUI.nviz source code](https://github.com/OSGeo/grass/tree/main/gui/wxpython/docs)
([history](https://github.com/OSGeo/grass/commits/main/gui/wxpython/docs))  
Accessed: Friday May 08 10:38:23 2026
