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Why Lights Don't Always Shine


QuickDraw3D uses vertex interpolation to calculate the pool of light cast by a light source. Because of this if the pool of light does not reach the vertex of an object no light will shine on that object.

The above image shows a block, a light source and the cone of light created by the light source. No vertices of the block pass through this pool of light and so it appears as though the light isn't shining when rendered in QuickDraw 3D.

Here the block has been cut into four smaller blocks and the pool of light passes through multiple verteces for each of these blocks. As a result the light is rendered as expected.

So if you encounter lights that don't seem to shine in QuickDraw 3D you need to trim the object the lights are shining on into a series of smaller objects.

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