nXtRender is designed to simulate real-world lighting. Use the following guidelines when lighting your model:
- Provide accurate information whenever possible. Avoid using unrealistic intensity levels for light sources.
- Set the units correctly for your drawing by using the AutoCAD _UNITS command. The lighting will not be correct unless the units are correct. For example, if your drawing is in millimeters, make sure that millimeters is specified.
- Adjust the overall brightness of your rendering by using the Brightness control on the rendering display. Do not attempt to adjust the overall scene brightness by changing the intensity of all of the light sources. nXtRender's automatic exposure adjustment will be working against you if you attempt to do this.
nXtRender provides four lighting presets which can help get you started when deciding how to light your model. There are many more lighting options available, but the presets are often sufficient for many different renderings. The Presets popdown list is available on the Lighting tab of the nXtRender palette. Choose the Preset which most closely resembles your scene:
- Studio mimics the lighting which might be found in a photographer's studio. It is most useful for rendering small to medium sized objects in isolation.
- Exterior is used for daylight simulations of architectural exteriors. A sun and natural sky are simulated.
- Interior Daylight allows you to simulate an architectural interior during the day, lit by natural light.
- Interior Lighting provides a simulation of an architectural interior at night, lit by artificial luminaires.
The primary lighting is provided by an high dynamic range image file (HDRI). The light from the HDRI has been artificially dimmed, to resemble the interior lighting levels of the studio. You can modify the HDRI settings and file on the Sky tab. You can add artificial lights to your scene using the Lights tab. The visible background in the Studio preset is black.
The sun and sky settings can be modified on the Sun tab. You can specify sun angles directly or you can use geographical location and date and time. The default visible background for this preset is the simulated sky.
Use Interior Lights as well as sun and sky for lighting.
For an interior daylight simulation to work properly, you must use a transparent material to represent the glass in your windows. Sun and sky settings are similar to the Exterior preset.
Also, you must add artificial lights to your model.
- See: The Lights Tab
Use Interior Lights only.
For Interior Lighting to work properly, you must add artificial lights to your model.
- See: The Lights Tab
Additional Notes on Presets
- Indirect lighting, the lighting reflected off of surfaces, is on when one of the two interior presets are selected and off for studio and exterior. This type of lighting is a very significant component of an interior simulation. For exteriors and studio models the effects of indirect lighting is more subtle. You can turn on indirect lighting for exteriors and studio models if you want this additional realism (at a substantial performance cost.)
- Interior daylight mode and exterior mode do not have artificial lights enabled. You can add artificial lights to these presets if you wish by following the procedure here.
- Night time renderings can be a little tricky. See this to get started.
See: nXtRender Lighting Basics Tutorial