Running nvis tool in QGIS GRASS

Question

I am trying to follow this workflow: [Generating DEM from contour Shapefile using QGIS?] and it's running fine, and when I hit view output or view results I end up with a flat raster with shading associated with the heights of my contours on screen.

However, I want to see the 3D terrain with hillshading etc, and potentially export a 3d mesh, and from research, think that the nvis module in GRASS can do this for me, but when I try to run this I get the error "module nvis not found", and QGIS crashes and dies.

When I go to Manage and Install Plugins, Grass is there, and it has let me perform all the other modules I've needed.

What do I do with this?

Link to sample data here (.shp+.gml): https://www.dropbox.com/sh/mwxlr3ij78d8gkr/lKwgu3Pafu

Answer 1

You have two solutions:

1) from the GRASS plugin: you are working in GRASS GIS, not in QGIS, so you need to know GRASS GIS

• you need to first open a LOCATION/MAPSET of GRASS (from the plugin) or create a new LOCATION/MAPSET

• you will then have access to the GRASS Tools

to:

• import the shapefile in the MAPSET (v.in.ogr.qgis)
• transform the shapefile in a raster if you want to use the r. modules (v.to.rast)
• fix the GRASS region (g.region)
• use r.contour, r.surf.idw, r.surf.idw2 or v.surf.rst to generate the DEM
• use nviz to visualise the DEM, change the color, drape a raster layer or add another DEM and/or vector files.

2) from GRASS in the Processing Toolbox:

• you are working in QGIS. In fact, the use of GRASS GIS is transparent, no need to open GRASS GIS, import the shapefile in a LOCATION/MAPSET or fixing a region, everything is done automatically by Processing.

3) What is the difference ?

The Processing version is more limited, you may only view the DEM, with no possibility to drape a raster, add another DEM or vector layers