Virtual islands

Using Genesis II

Introduction

I was delighted to find the article From cardboard cut-outs to virtual islands by Nick Piggot on the OS site. Somewhat prematurely I set the kids off on the model-making task, then downloaded Genesis II from the Geomantics website. Frustrated hours followed as I tried to get the software to work. While the latest version of Genesis (IV) promises a more intuitive experience, I perservered on the grounds that Genesis II is free and runs on a faily low spec PC. Once the basics have been grasped, users may want to upgrade. The purpose of this article is to provide a walkthrough for teachers wanting to use Genesis II in the classroom.

Geomantics have recently updated this tutorial for GenesisIV.

virtual island
Virtual landscape rendered in Genesis II

This whole article is a work in progress. Please visit this page to contribute ideas for improvements. I must stress that I am still learning how Genesis II works!



Walkthrough

Start by scanning a copy of a student's map as per the OS article. The map should be clear and legible, with plenty of contours drawn in a high contrast colour, and saved in bmp format.
scanned map
Scanned map [click to enlarge]

Create a folder in which to place project files including the scanned map. Start Genesis II and choose Projects / New Project and save into the folder you created a moment ago.
Choose the Landscape Heightfield Editor. Unless you have a square map, it will be necessary to create a new grid and adjust it to A4 size by clicking Landscape / New Grid and adjusting the grid points on the x axis to 210 and the y axis to 295.
new grid
New Grid dialogue

The map now approximates A4 dimensions. To set the background to the scanned image simply click the set Background button and browse for the scanned image.
set background
Set background to scanned map

There are a number of tools that can be used to generate the 3D topography, perhaps the most useful is the Trace Contour button. It is probably best to enlarge the map using the zoom tool before embarking. Select the Contour Trace button (coloured blue) and carefully click on a contour. With luck, the tool will pick out the entire contour in dark green, though if it is reluctant, try increasing the colour tolerance slider.
Contour trace
Contour Trace

Set the height of the contour in the pop-up box that follows. Initially this procedure can be fiddly, but it rapidly becomes easier with judicious use of the colour tolerance slider. When all the contours have been identified, it might be beneficial to add some selected spot heights with the appropriate tool before interpolating the rest of the height points on the map. To use the Interpolation tool, click the button, draw a rectangle over the area to be interpolated and Genesis II happily works out the height of all grid points on the map. If the results don't look something like the image below, and instead you are still looking at contours after using the interpolation tool then it is likely that you are experiencing a known bug. In this case you will have to select Trend Analysis instead of Nearest Neighbour interpolation. The result will be a landscape that is quite "stepped" in appearance. This was the case with my island.
Interpolation
Interpolation results

I found it a problem to work out how to add the sea around the island using the Flood with Water tool. There may well be a better method, but I add the water after interpolating rather than before.

The next stage is to render the landscape. Click the Landscape Renderer button and the redraw button. Initial results are likely to be disappointing.
render
First Render

Things to check on the Heightfield Editor are that the maximum height is set to an appropriate value, and the vertical scale is exaggerated as required. The next stage is to adjust the camera settings. This part can be very fiddly in Genesis II but try raising the height of the camera and adjusting the various values until the desired view is achieved. Note that artifacts spoiling the view could possibly result from having the camera buried in the island (check the settings), or rogue contours (3000m instead of 300m etc).

After each adjustment to the camera re-render the island. This process can be speeded up by checking the preview box in the Landscape render window.

At this point, islands that are too plateau-like can have their topography adjusted by careful use of spot heights and re-interpolating until the desired shape is achieved. The next stage is to improve the quality of the final image. Increasing the fractal recursion level from 1 to 2 in the drop-down box may have an effect on quality, and you will probably want to load one of the pre-set environments to see the various effects that are possible. Select Projects / Environmental Wizard, then render the landscape again.
This is my island with the late summer afternoon environment and fractal recursion set to 3.
final render
Final image

The next stage could be to tweak the environment settings, add vegetation or other layers to the island, or drape the original map over the contours. To add the original bitmap as an overlay, copy it into Genesis II's Overlays folder. From here it can be added to the 3D model via the Advanced tab. Go into the Terrain Layers Editor to define the overlay by giving it a name. Then check the boxes to draw over all terrain and adjust the transparency of the overlay to suit.
Final image with overlay
Default environment with scanned map as overlay