Low Mist Effect Tutorial
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Low Mist Effect Tutorial

This tutorial will show you how to create the appearance of a low mist in Terragen. It is not the only way to create mist, but it enables you to apply the effect to an existing image, so you can still have a blazing hot desert and a low lying mist, if you want.

Although this tutorial was written for Terragen, the basic principle can be used with Bryce, too. In fact, it's actually easier in Bryce, since you can directly render a height map, with no fuss.

For this tutorial you will need a good image editor - Adobe Photoshop is preferable, but any editor than can handle layers and layer masks will do. You will also need SOPack, a set of plugins by Sean O'Malley.

OK, here's what to do:
First, create your scene as normal, and render it and save the image.
On the left, you can see the one I'm using for this tutorial. Click on it for a larger view.

Download .TER (127K)
The next step is to export the terrain map as a .RAW and open it in your image editor. You then need to convert it to RGB (or True Colour, or 16 million colours, depending on the editor) and save it as a Windows Bitmap (.bmp).
You can see the terrain map I used on the left, and you can also download the corresponding .TER file.

Return to Terragen. Before going any further, I reccomend you save your Tg world to a new file, because we are going to make some pretty drastic changes to it.

Now, remove all surface maps except the base one (which you can't remove anyway). Click the base surface, then click the 'Edit' button. Set bumpiness to minimum and 'Mimic Terrain' to whatever you want - it doesn't matter since there are no bumps anyway.
Click the 'Tex' button and in the dialog that opens, click the '+' button and choose 'SO Image Overlay'.
The next dialog gives you a choice of overlay methods and terrain size. Choose 'Total Overlay' and set the terrain size option appropriately. When asked to locate a suitable bitmap, open the image you save previously (the terrain map one).

Open the Atmosphere dialog and set all the sliders to zero.
Now open the Lighting Conditions panel and move the sun directly overhead, and turn off all shadow casting options. Click the Background Light tab and set shadow lightness to full, and shadow colour to pure white.

Open the Cloudscape panel, and move the Density Shift slider all the way to the right - this will produce 100% cloud cover, in effect creating a white background.

Now, render a preview - it should look something like the image on the right. This will be the 'mist mask' - you can click the preview to see the full image I used.

If all is well, render the image at the same resolution and detail of the original, and open it in your image editor.
In the original image, create a new layer, then create a mask for it. Use the contents of the new image as the mask, and fill the entire layer with a suitable colour (like light grey). If you find the whole sky has been turned grey, you've got the mask the wrong way round - just make it negative and all should be well.

You may find that you'll need to play about with Levels/Curves/Gamma/whatever of the mask to get the mist to look right, but if everything goes according to plan, you should end up with something like the image on the left (click to enlarge).