May 31, 2012, 04:47:33 pm
The graphics card you're using just about meets the minimum requirement for Lumion, so you would experience shorter render times if upgrading was an option:http://www.videocardbenchmark.net/gpu.php?gpu=FirePro+V8700http://lumion3d.com/forum/f-a-q/lumion-2-minimum-hardware-requirements/About IES lights with dynamic shadows
Every time you add a light with real-time shadows (i.e. Shadow Cache
-> off instead of 128/256/512), the scene needs to be rendered once more, so the exponential render times you are experiencing are not surprising.
If you turn on FPS in Settings and press F8 + F9 while the entire scene is visible inside the viewport, you will be able to see how many vertices (3 vertices per triangle in a polygon) that Lumion needs to render for each frame. Notice how this value rises each time you add a light with dynamic shadows to the scene.
However, if you change the Shadow Cache
to one of the 3 resolutions (128/256/512), it means that the vertex count will drop dramatically. In other words, the graphics card has to render the scene fewer times per frame at the expense of a higher memory usage. This will almost always result in shorter render times.