Autocad 3d lighting

by Design Workshop Sydney

After modeling and applying textures in Autocad 3d, the whole scene is given a sense of realism by applying lighting. In this way we can also create accurate shadow mapping in an architectural model. This is just one of the many functions we explore in our Autocad 3d coursesautocad-3d-lighting
There are three types of light in Autocad. Firstly, Point Lights – in other 3d programs these are refererred to as Omni Lights. A Point Light is like a light bulb, casting light and shadows which spread out in all directions. The second type is a Spot Light and, like a spotlight in the real world, its shadows fan outwards from the source. And the third type of light is a Distant Light – this is like Sunlight where the shadows are parallel.
When adding lighting to a scene it’s a good idea to split the Screen into 4 viewports as follows: View > Viewports > 4 Viewports. Keep 3 orthogonal views in Wireframe mode and with Parallel projection, and the bottom right: Home > View > Realistic. This is a good method of viewing the objects in a scene relative to each other, especially if you have a large screen or, even better, a dual screen setup.
To create a Spotlight, go to the Lights tab > Create Light > Spot > Turn off Default Lighting (pre-2009: View > Render > Light > New Spot Light > Yes). Set a position: 500,500,500 (for example, or click anywhere & move it into position). For name call it Main Light > Enter twice and a light gizmo appears. Move the light if necessary. Then make sure the correct Viewport is selected and render the view by hitting the Render button.
The shadows may be too dark, so we add a softer Fill Light: Light > Point (Pre-2009: View > Render > Light > New Point Light, or type light > D > Enter). In traditional studio photography the Fill light is usually at right angles to the Main light source and about half the intensity. Name it Fill Light. Render the scene again.
This time it could be a bit washed out with two sets of shadows, therefore we’d need to modify the lights: click on the small arrow button in the Lights tab to open up the Lights in Model palette (Pre-2009: Tools > Palettes > Lights). Select Fill light > right-click > Properties (or double-click). Note that the properties appear on the top of the right-hand side panels – if you can’t see many properties, hold your cursor over the bottom dividing bar and click & drag downwards. Note the values for the light’s Intensity Factor, Colour, Position, Attenuation (falloff) and Shadows. Change the Intensity here > Shadows off. Note you can also change the lighting colour here. Keep the Main light Intensity Factor at 1 or 2. Close & Render again.
In the Output File list toggle between the last 3 renders, then select the one you prefer and right-click on the name in Bottom Left list, or File > Save > JPEG or TIFF are the best options usually. JPEGs are small in file size, but TIFFs are better quality. Therefore JPEGs are good for a first drafts and website images,and TIFFs are good for brochure/magazine presentations.
Note that Distant Lights emulate Sunlight with parallel shadows, but are best not used with Photometric – realistic – lights. You don’t get a gizmo for a Direction Light or Sunlight.
The 3d interface in Autocad is user-friendly and easy to learn, and we take time to teach a broad range of applications in our classes including modeling, materials, lighting and animation. See many examples of our clients’ work on our Facebook page.
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