Creating environments for your visualizations

When you have finished modelling, texturing and lighting your visualizations things will probably still look a bit stale. You can give your visualization context and placement if you create some simple and yet convincing props, such as skies, vegetation and people. As photorealism is the intended direction of architectural visualizations what better to use to beef up your realism than some intelligently placed photos.

Sprites

In order to seamlessly add photographic images into a 3D visualization we need to be able to mask out the parts of the photo we aren't interested in seeing (like the grey background in the image). By one means or another, a mask has to be created to make the image transparent in the grey sections and opaque in the coloured sections. Creating such a mask is a tutorial in itself. Using a green screen facility is one solution, but you can also purchase existing libraries of sprites (people, vegetation, cars etc...) from specialist companies such as Marlin Studios.
As such a simple shader can be made up using these two images mapped to a shader's colour and transparency channels respectively.


Apply the shader to the appropriately scaled NURBS plane A sprite will only cast shadows if you
use ray traced shadows

Sprites in this context can be used for people walking around inside or outside a 3D modelled house, they can be used for trees, grass, cars etc... You can even use animated sequences or people, cars, etc. The fundamental problem is that these are all 2D textures in a 3D world, and if you move your camera to one side of the sprite the illusion is lost. This is especially

The sprite's normals facing the camera A "flattering...er.. flattening" sideways glance

The illusion of depth from a 2D sprite can only be maintained if the sprite is always facing the camera (ie the surface normal always aims at the camera). This can be achieved using an aim constraint between the sprite's geometry and the shot camera.

Creating camera aim constraints for sprites

In order to correct this problem we have to create an aim constraint, such that the sprite's surface normal (the Y axis in our example) points towards the camera and so the sprite stays upright we orient its vertical vector (negative Z in our case) by creating an up vector in the negative Z direction..

So select first the object that is doing the constraining (the camera) then the object being constrained (the plane) and then;

Constrain > Aim

Change the Aim Vector to X = 0, Y = 1, Z = 0.
Change the Up Vector to X = 0, Y = 0, Z = -1.

Then click Add.

 


Sprite without aim constraint


Sprite with Y=1 aim constraint

Now the sprite turns to face the camera In all (reasonable) views

The sprite will now turn and face the camera

Exercise

You can see now that it would be an easy process to now make the woman above stand in a field of grass and trees. Two sprites are used here, a strip of sprite grass repeated several times and a simple tree.

Environments.

There are two easy ways to create a background sky for visualizations. One is to just change the camera environment colour to a blue colour, or create some geometry and apply a sky texture to it.

To change the camera colour, first select the camera, then open its attributes. Open the Environment folder and click on the colour swatch to choose a new background colour.

A more elegant approach would be to use some appropriately textured geometry.

There are two types of geometry skies you can use
- a hemisphere
- a cylinder (landscape)

Below are examples of textures that if mapped on to a NURBS hemisphere and cylinder respectively would give a nice sky. Consideration would have to be taken such that the objects are sufficiently scaled such that proper perspective is maintained.

 

Hemisphere Texture,
with the same texture applied to the previous scene		 Landscape Texture

Landscaping using Paint Effects and Particle Systems

In this section we are going to explore how you can use both surface particle emission and paint effects to create gardens for your visualization.

The idea is to put plants around a house in an organised manner.

We could just paint freestyle using a landscaping layout like the one shown on the right, but that is messy and time-consuming.

A much easier (in terms of labour) solution would be to let them grow for themselves.

To do this we will be planting particles as seeds on the ground where our plants are to grow. We can then use the particle instancer to instance a paint effects curve onto each particle.

Start with a landscaping layout, and using the Create Polygon Tool, trace out the section of the garder you want to work on.

(To be completed at a later date... sorry, email me if you want a quick explanation)