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  The "100 Proof" Method

WeightMaps Made Easy in LW 6.0

 Within Lightwave [6]'s Modeler, you can now setup your skeletal hierarchy for animation with a new feature called, "Skelegons". You can name, cut, copy, clone, mirror, size, stretch, etc. these (pre)bones. In LW[6], you no longer have to only rely on bone fall-off in Layout, you can now custom assign percentages of bone influence on a point per point basis for each bone. This weighted vertice technology, called "WeightMaps", is most useful in tweaking the how your mesh reacts at limb joints over a solid skin surface.
This "100 Proof" Method is just my simple approach for setting up WeightMaps to animate a lowpoly character model mainly for video game developers. It may, however, be useful for other applications too. It does not rely on any automated map generator, nor does it involve the pain staking task of airbrushing weights onto a mesh. Rather, its a quick and dirty hands on method that gives you a good start.
Note: Before continuing, please make sure you read and follow everything on page 1 & 2 of Customizing LW 6.0 Workflow because I'll be taking a lot for granted in regards to menu layout and certain installed plugins.

 Let's Begin...

This is the lowpoly model I'm going to use for the demo. It was provided by Tamara Michicich (mikicic@21stcentury.net).

It is roughly 5 feet 8 inch's tall and is made up of 680 polygon triangles in Layer One. The Limbs are symmetric.

Note: this model is facing positive Z, with her back out towards the screen.

Before we get to WeightMaps, we'll need some bones...

First we're going to create all the bones for the left side of her body. We'll begin this process in Layer Two, utilizing our new custom VMap Menu Tab. I will use DrawSkelegons to construct a skeleton hierarchy for her (VMap > Revise > DrawSkelegons). We'll first want to initialize the Root bone's rotations along the Z axis. So, in the Right View, start behind her waist pressing down and dragging straight right. Release the mouse button and continue to create the Pelvis bone by mouse clicking once at the pelvis. Now switch to the Back View to create the Hip bone in the same manner. Switch again to the Right View and create all the child leg bones by mouse clicking once at every joint position down the leg, starting at the knee and ending at the tip of her toes. Hit the Space Bar to release this draw mode. Make sure that the actual leg bones are in a straight line only when viewed from the Back View (same X value). This is important for setup in Layout, so we'll fix later. The extra heel foot bone is for visual reference to plant feet down on the floor when animating. It is created in the Right View by selecting the foot bone, turning on DrawSkelegons and clicking once at the heel. Notice it auto-snapped and auto-parented itself to the selected bone.

Finish the rest of her left side, up the chain from the Root bone using the same method, going back and forth between the Back & Right view ports. For this demo, lets make sure we keep the UpperTorso bone straight up along the Y axis (Same Z value). Notice there is only one bone for the head and no hand bones, just one at the wrist. This is because I prefer to use Endomorphs to animate them.

Now select each bone, one at a time, and use Rename. For this demo, we'll use a naming convention where all limb bones that branch off to the left have a "L_" in front of its name. You can select SkelegonTree to view your hierarchy and make sure that it is correct. You may also rename and change parenthoods in this window.

To finish the skeleton, select all the left side limb bones only and use Lightwave's Mirror tool (Multiply>Replicate>Mirror) to create the right side limbs. Once the tool is activated, drag it along y at the 0 x-position, hit the Spacebar to release the tool. Finally rename all these new right side bones by replacing the the "L" with a "R". To be safe, double check your skeletal structure with SkelegonTree and make sure everything is in order.

Finally we have all our bones, now lets get down to this so called "100 Proof" Method already!

First, if you have my config, you can use the Numeric Pad 2-Key to select a preset window scheme with the perspective window in Weight-Shade mode.

The method simply works like this; for every bone (except the Root), make a new WeightMap by selecting the vertices that you feel belong to that bone and mouse clicking on (new) in the lower right hand corner weight pull-down menu. A new window prompt will open. Type in the exact name of the bone leaving Initial Value checked and the value at 100%.

 

 

 

 

 

 

That's It ! ! !

The key thing to remember is that it is totally OK to overlap vertices from one WeightMap to another. In fact, I especially encourage it on points around joints. Yes, this means that two separate bones can have 100% influence assigned to the same exact point . Remember, I said it was a quick and dirty method. Even if you went in and made one bone pull that point at 50% and the other at 50%, you haven't disturbed the influence ratio, and you will get the same result.

Since this model's limbs are symmetric, I can follow this method and create only new WeightMaps for the all the centric bones and the left limbs. I'll then use a plugin by Yoichiro to generate the right side weightmaps for me. In the VMap Menu Tab, select Mirror WMap and a new window prompt will pop up. Following our naming convention, type "L_" for the Source Key and "R_" for the Target Key, then OK. Done.

Thanks Yoichiro!

Now we're ready to bring our lowpoly character model into Layout and see the WeightMaps in action. SAVE your model and exit Modeler.


Well, there you have it!

You should now have your character model boned & weighted and ready for animating. Once in Layout we'll convert our Skelegons into bones and see how our mesh reacts to our new WeightMaps. Then, we can easily go back and forth between Modeler and Layout and adjust our Weights until we get the result we're looking for.

OK, so lets take a look at what we've done in Layout...

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-last updated on 08.19.00-

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