Worksheet 5 - Lighting and rendering

Arnold Renderer

We will be using the Arnold Renderer in this worksheet as it will give us the best quality renders.

If you are using the lab machines the Arnold render will already be installed and you can skip ahead to "Create a new scene"

If you are on your own machine, you will have been given the option to install it when you installed Maya. If you have it you should see an Arnold menu item.

If you cannot see it, you may need to turn on the Arnold render by going to:

Windows > Settings/Preferences > Plug-in manager

Search for mtoa and tick the boxes.

If you cannot get this to work please ask for help.

Create a new scene

Open up Maya
Create a new Scene
Save the scene to a new folder.

Import fbx file

Import this pumpkin fbx file into Maya

pumpkin for rendering

import button

You should now be able to see an orange pumpkin model in your scene.

Test Render

To render the scene select Arnold > Render

This will open the Render View you will see that it is completely black. Why is this?

It is because you have no lights in your scene.
Close the Render View Window.

Add Basic Lights

On the menu bar, select Create > Lights > Directional Light

directional light

The light will be created at the origin, so move the light up above the model and rotate it so that the arrows point toward the model.
Only the rotation has an effect on directional lights, they are normally used to simulate a distant light source such as the Sun.

Turn On Lights and Shadows

You can get an rough approximation of what the light will look like in the final render by turning on lights in the scene.
You can do this in the panel menu

lights button

Turn on Shadows with the button to the right

light properties

With the directional light selected you can change the attributes.

light attributes

If you cannot see the attributes, click on the attributes button in the top right of the screen.
Experiment with the changing the colour and intensity.

Render the scene

Try to render the scene again, this time you should see something.

You should see that this renders the view from your camera.

Point lights

Add a point light

Move it inside the model

Increase the intensity to get a nice glow inside the pumpkin. You can type a number into the box, start with 200 if you cannot see anything.

Spot light

Add a spot light

Move it above the pumpkin and rotate it so that the cone point downwards

These lights have many more attributes.

Experiment with the Cone angle and Penumbra

You may want to add a polygon plane under your pumpkin so that you can see how the lights cast shadows on other objects.

Render your scene again to see how it looks.

Render Settings

Open the render settings by clicking the render settings button.

In the common tab, make sure you are rendering using the Arnold Renderer and change the Image format to jpg.

Next, scroll down and change the Image size Preset to hd_1080 This will mean your renders are full hd (1920 x 1080 pixels)

Render your scene again and see how it looks.

Saving your render

With the render view open, you can export your current render by selecting File > Save Image...

Choose a location and a file name and save the image.

Render Quality

You may find that your render quality is not very good. This can happen if you have low lighting or lots of complex objects in your scene.

You can adjust the render quality in the render settings panel.

Open the render settings panel

In the Arnold tab you can increase the number of samples. Start by slowly increasing the AA samples.

Be careful, increasing the samples will improve your render quality but the render time will increase exponentially.

More information about these settings can be found here:

https://help.autodesk.com/view/ARNOL/ENU/?guid=arnold_user_guide_ac_render_settings_ac_samples_html

Challenge

Experiment with different lights

We have covered the basic lights in this worksheet but there other useful Arnold specific lights you may want to use.

You can find them in the top menu, under Arnold > Lights

The skydome light creates a large sphere of light around your model.
The area light is great for simulating windows or other larger sources of light. It can be scaled, the line show which side is emitting light.

Emissions

Standard Surface materials support emmisions, they can glow.

Add some spheres for eyes
Apply a new standard surface material to them
Increase the emission weight and colour