Lightwave tree tutorial

To continue to the noise tutorial click HERE !!!

Howto: fake tree shadows, to save memory on large projects.

Sometimes, when you need hundreds off trees in an animation, you need to econymise
with system recourses. Even if you have 256 megs or more installed on your systems.
This tutorial shows you how to do that, "Let the machines work smarter not harder".
Notice: For this tutorial you will need basic Lightwave skills.

To succeed with this technique, everything depends on the the right bitmaps, tree maps are reqied, one bitmap for projection map for making the fake shadow, and two maps for the tree,be sure the map got the right size, at least 600 pixels on the short side of the map, and be sure to have enough space between the leaves. The maps below, of a young tree is those, i will use in this tutorial, and in the tutorial for 3ds Max witch i am planning to do. The opacity map tree_op.TGA could be inverted, but then you would have to make it negative for use in 3ds Max. Trees can also be made with clip maps but, i think the result look a bit too "sharp" for my taste.

Start by making two crossing polys in modeller, make them 2 sided, and give them each a different material name.	Notice: if you select the polys one by one, and press the "w" bottom you can easily check the axis off the normals, by selecting them in "polygon statistics".You need that information later in layout.



Next you have to create a ground for the tree, you need it to make the shadows visible. Remember to flip the poly's in the direction off the y axis.



Now it's time to load the image files into layout in the images panel, and then apply them to the poly's in the sufaces panel. Apply automatic sizing and the proper texture axis. Here you need the information from modeller. Note:For this bitmap i used an "antialiasing strength off 0,2



Now open the transparency menu in surfaces panel.Then go through the same steps for the opacity map, except here you turn on the negative bottom and there is no need for antaliasing. Now set up a small scene with two lights,one directional and one spotlight, directed just above the tree, then open the lights panel and select the spotlight, and as projection image select the bitmap to use as projection image. Adjust the spotlight cone angle to match the proportions of the tree map.



Now place the spotlight just above the tree, and make a test render. You may have to play around with the shadow angle and distance, to get the wanted result.	Notice: turn off shadowcasting on all lights and in the"objects menu" chose the "appearance options" menu and turn off "self shadow,cast shadow,recieve shadow" for the tree object.



Opacity mapped trees also works brilliant with shadow casting turned on, together with ray traced shadows, but use them only in smaller scenes and for stills.