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Alex Pitt
11-18-2003, 04:17 PM
Background
I’m trying to do one of those fancy ‘Architectural Walkthroughs’ using Lightwave7.5.

Problem
The particular interior I’m modelling features some concealed neon lighting running around the ceiling perimeter which gives a linear fall-off effect. (See Attached Pic RACeiling.jpg). I was trying bake this effect onto a surface using a stretched linear light positioned right up against the ceiling polys. The bake came out funny.

Bug?
To try to isolate the potential bug I started a new ‘stripped down’ scene using these steps:

In Modeller
1. Create a single rectangular poly in a horizontal orientation (10mx5m) Centre 0,0,0. (I left it with Default surface.)
2. Texture-map it & send to layout.

In Layout
1. Orient the camera to look at the face of the poly.

2. Create a new linear light (Call it Neon). Under properties for the new light, set intensity to 100%, distance falloff to Inverse^2 & Range to 2.5m

3. Turn off any other lights in the scene

4. Stretch the linear light to 10m long and position it just below the poly and to one side.

5. In the surface editor, add the Surface Baker under the ‘shaders’ tab of the Default surface.

6. Use the default Baker properties but under ‘UV Map’, select the texture map created in modeller & set ‘image type’ to LW Jpeg. Choose a file name & location under ‘Image Base name’.

7. If you’re lucky enough to have it, turn off ‘multi-threading’ under render options. (i.e. set multithreading to ‘1 thread’) & hit F9 to render a frame.

See attached Pic BakerBug.jpg

When you render (apart from a little grain) you get the desired effect. (Hurrah!)

But the baked image looks totally different; as if 4 or 5 point lights were used instead of a single smooth linear light. (Bugger!)

When I moved the linear light away from the poly, (and re-rendered) the baked image changes to look more like a single point light, still far from the effect in the rendered frame. What’s going on? (Or what I’m doing wrong?)

If anyone can help or advise, I will be very grateful indeed.

Best regards

Alex Pitt