Getting Started
with VNS 3: Lakes &
Streams
Part 6C. Area Terraffector Lakebed
1. Lakes are a 2-step process
if you're not filling an existing depression. You dig out a lake
bed with an Area Terraffector and add water with a Lake.
Go to the Terrain Task Mode. Like many Components so far,
we could use the Create button to make a new vector-Area Terraffector
combo. But we already have the Lake vector, so select the Area
Terraffectors category in the Scene-at-a-Glance and Add Component of this type.
2. Name it Lake.
3. Expand the Area Terraffectors
category.
4. Move down to the lower Scene-at-a-Glance list and expand the Vectors category.
5. Click and drag the Lake
Vector up and drop it on the Lake Area Terraffector. Confirm
the operation.
6. Go to the Elevation &
Roughness page. An Area Terraffector will raise or lower
terrain depending on the Elevation and whether it's Relative
to ground or an Absolute value. Leave the Lake Relative
and make the Elevation -50 meters to dig a hole 50 meters
below the terrain.
7. Save the project and render
a Plan preview.
8. Switch back to realtime mode.
VNS has Terraffector Preview that you can turn on from
View Preferences. This can be useful when working with close
views on small sections of high-resolution terrain. For large
area effects, memory demands and detail limitations of realtime
preview usually make preview renders a better choice.
9. Let's load another camera
at the east end of the lake. Go to the Render Task Mode,
Cameras category, and Add Component from Gallery.
10. Load the Lake View.
11. Do not scale the Camera's
position to the current DEM bounds.
12. Open the Lake View
Camera in the upper left view. Save the project and render a
preview.
13. We can't see much with the
default morning light. Go to the lower Scene-at-a-Glance pane
and open the Light
Editor. Turn to the Position
& Orientation page and change the time of day to 3:00
pm. Save the project and render a preview.
14. By default, Area Terraffectors
raise or lower terrain with a vertical cliff. To create a gentle
slope inward from the vector, we need an Edge Feathering Profile.
15. Bring Area Terraffector Editor forward. Turn to the General
page, select Use Profile, and Edit Profile.
16. For an Area Terraffector,
the profile starts at the vector on the left side of the graph.
As we move right along the curve, we're moving inward the vector.
Think of the vertical scale Value as a percent of the
Elevation we set, in this case -50 meters.
17. The default profile starts
at Distance 0 and Value 0. That means no elevation
change at the vector. The profile ends at a Distance of
10 meters and a Value of 100. That's a full
elevation change 10 meters in from the vector. That would be
rather steep for our lake.
18. Select the right point and
change its Distance to 150 meters, which would
be more appropriate for a 50-meter-deep lake.
19. Select Add Point and
click on the profile. Change the Distance to 60
meters.
20. Change the Value to
20 and the Tension to 1. The lake bed will
slope down to a depth of 20% of 50 meters, or 10 meters, flatten
off briefly, then drop to its 50-meter maximum.
21. Keep the profile, save the
project and render a preview. We now have a shallow slope at
the edge of our lakebed.
|
