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Old 9th Aug 2008, 07:41 PM   #1
Contributing Member
LightWave Maya ZBrush
Join Date: Jan 2008
Location: Quebec City, Canada
Posts: 714
Default FF TUTORIAL - Surface Patching

As with the technique shown in the extruding along a curve tutorial, this one is the direct result of workflow habits I've learned to use in Maya that I think would make an excellent addition to the Lightwave modeler. This time around I will show you how to repatch surfaces that will result in a uniform SubD asset. Sound confusing? It might be for those who havent tried Maya before.

Allow me to explain. When we create intricate organic shapes, we patch specific areas, in very specific orders - usually. Take a head model for example. We *should* be starting with the eye socket. And then maybe we'll build the nose followed by the cheeks. Next comes the mouth, then maybe the forehead, etc... you get the drill. All the while we are doing this, we are paying the utmost attention to polyflow (loops), alignment and vertex count so that all the various parts will merge neatly into one another without all sorts of stray points and whatnot.

Well, in my wanderings in Maya, I've learned not to pay so much attention in the initial modeling of my assets as I would in LW. That is because in Maya, there is a function called going Live, that allows one to put all of the parts of say, a face model, into a BG layer, where you can draw new curves along the faces, constrained to them. In this fashion, you can have various portions of the face having differing poly densities and it matters not, because it will be repatched by one solid, uniform surface.

To facilitate this, we need a freebie plugins which you can download here -> Once its downloaded, unzip it into your plugins folder and add it into modeler. The rest, as always, is a matter of native LW tools.

Note: In this tutorial, I will be demonstrating only. The plugin is provided so that you will have it for later usage.


The first thing I want you to do is to examine the image below and note that there are three distinct surfaces, of varying polygon density and flow. If these three surfaces were of equal poly count, I could simply merge them together to make a uniform and solid surface.

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For the next step in the sequence, I've reverted back to polygon mode, and this is ESSENTIAL! If you are not in polygon mode, the plugin will not work. That being said, I've selected a small portion of the three surfaces for demonstration purposes, and placed them into the BG Layer.

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Now is the time to activate the plugin. If you havent assigned it a place on your menus, you should or at the very least assign it to a hotkey. It will be that important to your work later, as you'll be using it a lot for the repatching.

With the plugin selected, I choose to work in the Perspective window so I can rotate and zoom as needed. This plugin functions much like the ADD POINTS tool, left click-drag to move the cursor without placing the point and right click to make a point at the cursor. So, place the cursor along the edge of your geometry and then right click to start the point placement. Move along the surface of the BG geometry placing points as you go.

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Once you've worked your way along the three surfaces, you can rotate around and see that the points are constrained to the surfaces in the BG layer.

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Once you have the points laid out that you want for this section, press space to drop the tool, and then switch to point mode. You'll see all of your new points highlighted for you, ready to be converted into a spline. Press CONTROL-P (or use the menu button CREATE OPEN CURVE) to create an open curve.

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Continue doing this point placement, spline creation technique until you have the section you want patched outlined with the newly created splines. For simplicity's sake, I've only done three splines...

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Select the spline from one direction to the other, per the lofting technique tutorial. Once selected, you can then activate the loft tool. Be sure not to close the loft. You can set your span parameters to suit your final polygon requirements. And whether or not you keep your curves is entirely up to you, and the task at hand. If you are doing it piecemeal for whatever reason, be sure to keep your two outer splines so that you can do the next section of the new surface patch using them - in this fashion, your two patched surfaces will share vertices and can be merged with no tweaking of points.

Below is the resulting loft.

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You can see that now, the newly patched surface follows the contours of the BG layer. In the example, my upper extent is raised higher than the BG layer. This is normal. Once you have another patch created above it, and merged the two together, those specific points will realign to the geometry in the BG layer.

So, again, looking at the BG geometry, you can see three surface patches with poly depths of 4 spans, 6 spans and 4 spans respectively. All three are not connected in any way, other than from sharing common extent splines to simulate a conscious desire to line up my patches - but the poly counts are way different, and thus a point merge would not work...

-----> TUTORIAL ENDS <---

With this technique, you are increasing your work time somewhat in the beginning, but you are a little more free to simply model without the conscious effort of making everything perfect from the start. And that, depending on your comfort level and eventual proficiency with the technique may work towards reducing the overall time taken on an asset.

As with prior tutorials, I hope this bridging of the applications assists you.


EDIT: To be fair to the author of the plugin, I am providing a direct link to his website, where you can also download the companion plugin Move Point on BG, which allows you to interactively drag points across the surfaces in the BG layer. Great for using the same spline over and over again, instead of creating new ones for every junction. Once the copy is placed, you simply need tweak the points, and they will constrain themselves to the underlying geometry.

You can DL ADD and MOVE on BG here ->
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