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IMPORTANT: To view the tutorial with larger images and screen shots please download the PDF or XPS files.
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This tutorial was written exclusively for The3dStudio.com by Rick Johnston of Dreamscape Studios (Member Link).
*** Building a Sky Environment (in Photoshop and 3ds max) ***
Building a Sky Environment
If you have ever been flying over a long distance or on multiple occasions, you know from observation how much the sky will vary in lighting, color, cloud formations, shadows and obscurity. It can be the darkest of blues at high altitude and gradually changing to a very light blue near the surface of the earth.
To build a realistic sky environment can take a lot of time and effort. One of the largest impacts on the environment is not the sky background but the ground below if your camera angles allow the viewer to see the ground.
There are five elements to the sky environment. The atmosphere, ground, lighting, obscurity and clouds are all elements commonly found in the sky environment. You could have more depending on how large, how detailed and how realistic you want the environment.
I will only cover a couple in detail here and the others I will cover only briefly now but may cover them in more detail in future tutorials. The first environment element is the atmosphere. This is the envelope where the sky exists between the vast void of space and earth.
The atmosphere element is easily done in 3ds Max. Your results will vary according to the size of the maps involved, the time you take to build it and the lighting and camera settings you use to create it.
The ground is the next element. How much detail is seen on the ground will depend on the altitude of your camera and the angles and camera settings. In reality if you were flying at say 2,000 feet and looking straight down, cars look to be smaller than the size of Hot Wheels toy cars and buildings the size of match boxes. A lot of details are still visible to the viewer.
At ten thousand feet, cars are now specks smaller than ants moving slowly along paths and buildings are very small boxes. Roads look like very narrow ribbons at 2000 feet and just thin lines at 10,000 feet. Forestry which at 2000 feet you could see individual trees are now rough green pile carpeting. Building a ground environment will be covered in several separate tutorials later. For the purpose of this tutorial I will only give a cursory description of that process and I will supply some maps to do the tutorial.
Fog or Obscurity comes from water vapor, smog and dust in the air. This can be difficult or easy to create depending on the amount and type of obscurity. I will not cover this and we will use an unlimited visibility for this tutorial. Visibility in the air can range from 0 to unlimited in reality and adding these conditions can help the realistic appearance of your environment. I will cover this in a later tutorial.
Clouds can vary from a gray green almost glowing to a bright shimmering white and their shapes from feathery looking cirrus clouds to puffy looking nimbus clouds. Building models of clouds can be easily done for clouds that appear to be miles away but much more difficult for those you will penetrate with the camera in an animation.
The steps in building this environment will be.
Create the Sky diffuse map using Photoshop
Create the Atmosphere or Sky Model
Create the Ground Textures
Create the Ground Plane
Create lighting
Create camera view
Sky Diffuse Material Sky1.jpg
Create the Sky Diffuse Map
The diffuse map for the sky can be as simple of difficult as you want to make it. The weather conditions of enveloping cold fronts, warm fronts or stationary fronts will create clouds of different sizes, shapes, colors and types at various altitudes and these must be accurately represented on your sky materials and or modeled to accurately represent the cloud formations within the environment. For the purpose of this tutorial, a light cirrus cloud layer will be visible on the horizon indicating an approaching cold front. Other than that the appearance of the sky will be simple for you to build.
Open Photoshop and start a new image file. Call it Sky.jpg. The image size should be 28 inches wide by 14 inches high and have a 300 dpi resolution. See Fig 1-1
Fig 1-1
Image of Display with new file created. Save the file as Sky.jpg
Set the Foreground color to a very light blue. See Fig 1-2
Fig 1-2
Image showing light blue color selection in Photoshop
For the Background color select a medium blue with a gray tint in it. See Fig 1-3.
Fig 1-3
Image of Darker Gray Blue Color Selection in Photoshop
Now using the gradient tool, select a starting point with the light blue at the bottom of your image and then an ending point at the top with the dark blue gray. See Fig 1-4
Fig 1-4
Image of completed gradient color filling the Sky.jpg in Photoshop
Once this has been completed, the next step is to put into the image some distant cloud effects.
Select a new foreground color of very light blue. See Fig 1-5
Fig 1-5
Image of very light blue color selection in Photoshop
Select the brush tool with the 17 size and blurred edge setting. See fig 1-6
Fig 1-6
Image of Brush Selection in Photoshop
Create some very light white streaks that move up the top left just slightly. Place them in groups with a non-uniform length but a fairly uniform appearance. They should be just above the lower border of the image and not exceed a couple of inches in height. They will move from right up and to the left. See fig 1-7.
Fig 1-7
Image of Finished Sky.jpg in Photoshop
Start a new image called Sky1.jpg and make it 300 dpi, inches wide and 14 inches high. Copy the entire image from Sky.jpg to the left side of Sky1.jpg. Make sure to align it very closely to the edges of the new image. See F-1-8
Fig 1-8
Now copy the image from the left side of the new Sky1 image to the right side and the using the edit transform, flip it horizontally to get an opposite image on the right side. Line this up on the far right side. Then copy the far left or far right side to the center of the image to cover the white. See Fig 1-9
Fig 1-9
Image of the larger Sky1.jpg now with the copy of sky.jpg on both sides. Note that the right side copy has been flipped horizontally.
Now brush a few clouds in the center to blend the two sides together. Now using the brush tool and blobbing or streaking the brush across the clouds create a different appearance for the clouds on left and right sides. Try to keep your streaks aligned with the streaks you used for the clouds. It doesn’t take much effort to really change the appearance. See fig 1-10
Fig 1-10
Image of the nearly completed Sky1.jpg. Note that the view is zoomed in to reveal the additional cloud brushing to be added.
Now save the Sky1.jpgyou’re your materials for the sky are ready.
Fig 1-11
Image shows file save manager in Photoshop with the sky.jpg being saved.
Save the earlier smaller image as Sky.jpg and you can use it for an environment with a smaller view later. See Fig 1-11
Fig 1-12
Sky.jpg
Fig 1-12
Sky1.jpg
Create the Ground Texture using Photoshop
Creation of ground materials and textures will be in a later tutorial however I have provided materials for the ground and bump for you. These textures are free for you to use in doing this tutorial, but are not to be used in projects commercially. They are for use in this tutorial only for educational and learning assistance.
To create your own there are several methods. If you can get a copyright free satellite image from the desired altitude of the terrain you wish to use. Start there. Use that and Photoshop to create a bump map to match it. If you really want to get involved, you can use this satellite image to build a map and then using 3DS Max, create models for all the objects in the image. Houses, buildings, ground, trees and so on. This could be a very lengthy and time consuming effort. Providing your modeling skills are good and you do not use high count polygon trees, this could be very effective.
For now, you can use the materials I have provided here for this tutorial. See Fig 2-0 and 2-0a below:
Fig 2-0
Ground Diffuse provided in this tutorial. 495.jpg
Fig 2-0a
Ground texture provided for this tutorial. 495bmp.jpg
Create the Atmosphere or Sky
The atmosphere is approximately 27,120 miles in diameter but it is unrealistic to try and do this in 3ds Max. We need an environment that will about 40 miles in diameter, or at least appears to be. The materials we created and I have provided will help to do this.
Build a sphere with a diameter of about 300. Then using the non-uniform scaling tool, reduce the height of the sphere to about half the diameter. See Fig 2-2
Fig 2-1
Image showing the creation and squeezing of a sphere to be used for the atmosphere.
Add the material you have created called sky1.jpg to the material manager in the first box. Make sure the material is two sided. Then apply it to the sphere and apply a cylindrical UVW mapping. Change the height of the UVW mapping to about 322 and with the gizmo selected move the top edge of the mapping to align with the top of the sphere. This will place the clouds at just above the horizon level.
See Fig 2-2
Fig 2-2
Image showing the sphere with the Sky1.jpg added from material manager.
Create the Ground
Now create a plane in the top view that exceeds the outside boundary of the sphere on all sides. See Fig 2-3
Fig 2-3
Using the material manager build a material in the 2nd box. Select the materials provided in this tutorial called 495.jpg as the diffuse material and 495bmp.jpg as a bump map with a bump setting of 50. Apply the material to the plane that represents the ground and apply a planar UVW to fit. See Fig 2-4
Fig 2-4
Image showing the plane and the adding of the material from the 2nd box in the material manager
Create lighting
Add an Omni light located on the left side of the sphere and just inside its borders. Now move the light up and to the right along the inside of the border of the sphere until it is located as shown in Fig 3-1
Fig 3-1
Image shows placement of the omni light and the intensity.
The settings for this omni light are 1.65 intensity, shadows on, advanced raytrace shadows and shadows at .65
Create camera view
Create a target camera located in the front of the sphere just above the ground plane and inside the sphere itself. The target of this camera should be the rear of the sphere just above the ground. See fig 3-2
Fig 3-2
Set the camera view active in the bottom right window.
Now select the target of the camera and move it to the right side of the sphere. See fig 3-4
Fig 3-4
Image showing the camera location. Move the camera target to the right side of the sphere near the quad. The image in the camera view should change as the target is moved.
Turn the keyframer on to animate the target and move the slide to the 300 frame at the end of the animation. Then move the target to the opposite side of the sphere. Turn the keyframer off and deselect the target.
Render the animation.
Notice that the area closest to the ground seems to have a white and then above green glow. This is due to the camera settings and is fairly realistic with the appearance of sky in many cases. It looks like after sunrise with a haze in the distance. Lesser light intensity settings will gradually change the appearance and give you a different effect. Play around with these settings and find the result you want.
Now you can review your results. You may decide to use the Sky1.jpg material and edit it to add different cloud formations and sky conditions. Be sure to save these changed files to different names so that the original sky1.jpg remains as is.
Good modeling.
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