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9. Modifying a 3D Model |
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 MODELER, MASTERING 3D OBJECT CREATION At the beginning of working with any 3D sculpture program, it seems daunting to get rid of anything you create as it seems like it is impossible to get it back again. However, to truly be master over your 3D world, you must feel free to split polygons, or delete and create points and polygons whenever you'd like. sometimes you will find that you need more polygons to to increase the detail of a contour. You will find that having only four rows of polygons around the head, for example, would be very hard to get the detail you would want to have. Once you've gotten a roughed out form, it is invariable that you will want to add and remove polygons if only to find which way works best. When working with Subsurfacing mode, ensuring that exactly four lines enter every point will give you the least puckered object. IMPORTANT - Subsurfacing mode only allows 3 or 4 sided polygons and is smoothest when exactly four lines connect to every point. Those two rules necessitate your planning out your object. You will find that whenever you pass from an area which has more polygons to an area that has less polygons you invariably will end up somewhere having to have points where five (or even more) lines attach to that point. Experimenting with different locations for these five line junction points so that you minimize the puckering might mean that you must delete whole sections to try other methods of routing the polygons. It is also possible that you will accidently delete polygons that are hiding on the other side of your model as you work. It is often that after working on one side of an object while in Wireframe mode that you suddenly find that some polygon way in the toe got selected along with one you were working on and you deleted it. Oftentimes, the undos don't reach back that far in time. So, in this tutorial, I will show how easy it is to do such things. MODELER, TURN OFF SUBSURFACE TO MODIFY POLYGONS/POINTS Make sure no polygons are selected (implying 'All Polygons') and press the TAB key to exit from Subsurfacing mode. The object should suddenly grow sharp spikes, having tall peaks and deep valleys.  IMPORTANT - You can also zoom in and out in the Perspective window by holding down both the ALT and CTRL keys while clicking with the left mouse button and moving in and out. MODELER, HIDING BACK POLYGONS SO THEY DON'T GET IN THE WAY Widen the 'Right' viewport so you can see the full figure.   MODELER, TAKE CARE BEFORE HIDING THEM It is a good idea to first can deselect any polygons you may not wish to be hidden by going to the Perspective window. Rotate the object, selecting and deselecting as you would until the proper ones which you want to be hidden are selected. Press the minus key next to the zero key on the top row of your keyboad (or Display tab, Visibility section, 'Hide Sel') to hide the selected polygons. After hiding some of the polygons, at any time you can select more polygons, again hit the minus key, and those will also disappear. (You can bring back all of the hidden polygons at once by hitting the '\' key or by choosing Display Tab, Visibility section, 'Unhide'). Those polygons are now out of our way so they won't accidently get deleted as we work on the front ones. MODELER, ADDED A NEW LINE OF POINTS Here is what a new row of points on the left side of the centerline, added between the two existing rows of points, looks like after I've added it. I will now do the same thing to the right side of the head and body.  Select polygon mode by pressing CTRL-SHIFT-H, make sure no other polygons are currently selected, select one polygon, press ']' to select all connected polygons. IMPORTANT - In order to split a polygon, that polygon must first be selected. (You will be instantly shifting over to point mode after the polygon selection, though, so won't be able to know whether it is selected or not while in the points mode). Now, go to 'Points' mode by pressing CTRL-SHIFT-G, and choose 'Add Points' from the 'Subdivide' section of the 'Contruct' tab. The cursor changes to a small black plus sign with a white curved line to the bottom right of it.  Click with the black cross upon any edge and a white deselected point will appear. Click halfway along each line in a row, keeping track of being 'in between' the two rows you wish to add the line between. Use your ALT key to rotate wherever you need to see where the next point should go. I have selected each point afterwards so you can see the progression of added points. Notice that so far they are just points, there are no connecting lines making them into split polygons.  If you moved one of those center points you're creating just a little, you would see that they are really five (or six-sided) polygons that you're creating. It's five-sided if there are five dots and six-sided if there are six dots. IMPORTANT - Sometimes it is hard to see a polygon as being five or six-sided if two or more edges of that polygon line up with each other. Count the number of dots around any enclosed space to determine how many sides it has. Four dots = four sided. Five dots = five sided. So, that would make both of these polygons six-sided.  MODELER, SPLITTING POLYGONS Now, as I mentioned before, in order to split a polygon two things must be true. First, the polygon must be selected, second, two points need to be selected. So, this is using two different modes at once. Obviously, you can't see both at the same time. Also, split doesn't always work even if both of these things are true. You'll be splitting one polygon and it splits fine, and the next one just beside it looks the same but it won't split. In that case, it is better to just select that polygon, press the delete key to remove it, making the polygons by hand by selecting the points in a circle one-by-one, pressing 'p' to make the polygon. In this case, you need to do that twice to make two polygons. The only problem with doing it that way is if the polygon were originally defined in a surface name. If it were defined, that definition will be removed. You would have to reselect the two new polygons, and add them back to that surface name. But, much of the time, it DOES work so lets use that tactic whenever we can. To make things easier, I just select all polygons first, as I had said. That way I can split any two edges that I want to. You enter into 'Point' mode by pressing CTRL-h and highlight the two points you want the split to follow. You then tell it to split the polygon along those two points by choosing 'Split' from the 'Subdivide' section of the 'Construct' tab or by pressing CTRL-L. I have done two splits already, and have highlit two points for a third split in this image.    I save it out, do a 'File->Save Object As...' to give it another name to do an experiment. I decide that the face will need more polygons for the detail needed where the eye bulges out. I figure I'll try letting Lightwave subdivide the polygons for me this time, so I select the polygons in the face and follow them around the back of the head in a cylindrical band. I select Subdivide and choose the default values, clicking 'OK'.  These center points will have to be connected with split lines forming three triangles per polygon (as it takes three polygons to divide a five-sided polygon). I use the same techniques I outlined for splitting a polygon in half, but don't create the points, I just use the CTRL-SHIFT-L splitting triangles between the new point and the two far corner points on the opposite side of the polygon away from the newly created point. Until these unconnected points are connected to other points, Subdivide will give an error and that edge will leave a big gap in the object.  MODELER, REDEFINING FrontPolygons and BackPolygons SURFACE NAMES Now, I press CTRL-SHIFT-H to enter Polygon Mode, make sure all polygons are deselected, press 'w' to bring up the Polygon Statistics panel, select the FrontPolygons surface name, click the '+' to select all Front polygons, and see which polygons are now unselected. I did so many new polygons in that area, I'm sure that LightWave tripped up a couple times. There are about ten polygons which I SHIFT-add with left mouse button and when I have them all highlit, I press 'q' to bring up the 'Change Surface' panel and select 'FrontPolygons' from the drop-down menu, clicking 'OK'. I find that there are two polygons in the head which need to be added to the 'BackPolygons' surface name and I add them to the 'Change Surface' surface name in the same manner. I am now ready to try applying the surface textures, and rendering the figurine. |
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