Introduction
It is important to understand and appreciate just what bump maps are capable of, and how they can be used to enhance your Poser- and Bryce-created artwork. In this tutorial you will be creating a bump map for the nude Poser Male to make it look like he is wearing a tight-fitting body suit, building in some wrinkles and surface details with the bump map.
I often feel that bump maps are the most underutilized tool in the 3D artist’s arsenal, and this tutorial hopefully will give you a bit more insight into how to create and work with them – and to get them working for you!
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Step 1 - What is a Bump Map?
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Bump Maps, in simple terms, are bitmaps that utilize depth values that when applied to a 3D object simulate the appearance of a rough surface. Depth values are created using a gray scale where the lighter tones (more towards white) are used to simulate raised details and darker tones (more towards black) to simulate the impressed details.
Here's how bump maps work:
Here a bitmap with a grayscale gradient applied to a flat surface. From the top it would look like this.
But if rotated in three dimensions and the grayscale values used as a bump map, the following result will be createdWith the technical stuff behind us it is now time to get into the nitty-gritty of creating a bumpmap.
Imagine for a moment that the grayscale of the bump map represents a cross-section of a mountain. All the darker values belong in the valley and the lighter values on the peak of that mountain. The tones in the middle would be halfway up (or down) the mountain, on the slopes.
The grayscale is a scale of grays from pure white to pure black. They are represented by 256 tonal values, or 0 to 255. Pure White is 255 Red, 255 Green and 255 Blue. Pure Black is 0 Red, 0 Green and 0 Blue. The mid-gray (or 50% gray) is 127 Red, 127 Green and 127 Blue. (Note that I don't use 128 as a value because if 0 is the starting value and 255 is the end value then 127 is in fact the middle, but a single digit doesn't make that much of a difference. Grays are created with EQUAL values of the Red, Green and Blue components)
I treat mid-grays as the "plains" of the bump map, laying a mid-gray tone down for the bump map and working in the "valleys" and the "mountain peaks" on either side of that middle ground. |
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In this tutorial you will be creating a bump map for the nude Poser Male. You will try to make it look like he is wearing a tight-fitting body suit, but will build in some wrinkles and surface details with the bump map.
1. Firstly you need a basic texture map or template to work with. Use Steve Cox's UVMapper to do this.
But first start up Poser and load the desired figure you want. Leave the figure in the default pose. (we just want to extract the UV Map from it)
2. Export it as a WaveFront OBJ file.
3. Ensure the Export settings are left as such.
4. Now start up UVMapper and before loading the WaveFront OBJ file use the Settings and ensure that the output map is 1024 X 1024 pixels - it is easier to work with.
5. Because this was a default Poser figure, there will be an embedded UV Map with it and UVMapper will detect it and display it correctly.
The results should look like this.
6. Now Save the texture map.
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Step 3 - Setting Up a Bump Map
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Now it is time to fire up your paint program. I mainly use Corel Photopaint 8 & 9, but I am sure that Adobe Photoshop will work just as well with this method, but may need some adaptation.
1. Load the exported UV Map.
2. Convert it from a 16-colour bitmap to a 24-bit bitmap. (Mode...RGB (24-bit) bitmap). (UV Mapper saves its files as 16-colour picture).
Before we go any further you will have to draw in some important reference points. Because the UV map consists of 2 halves, a front and a back, the bump map texture must be created so that the seams will meet up. (I found these templates by "SnowSultan" to be very useful.)
Male Seam Template
Female Seam Template
3. Mark important points like the edge of where you want a collar to be or where the hip joints are. A 2-pixel brush with a bright colour such as red can be used to create the lines.
(Draw outside the template extents and one or two pixels into the map area to create a visible line on the rendering.)
4. This is very much a touch-and-go process. Often to test whether or not the textures line up, I keep Poser running in the background. (You will need a fairly fast PC with enough RAM to do this successfully - I currently have 256Mb but this process works with 64Mb)
5. In Poser, Load the figure, go to Materials.
6. Load the UV Map that you have just been working with. (Here's a important tip: Load it as a texture and NOT as a Bump Map for now as you just want to see if the halves line up correctly. If you load it as a bump map, Poser will create a .BUM file and that file will be used. If you then change the original bump map file in Corel PhotoPaint it will not be updated in Poser, and furthermore if you delete the BUM file Poser will not be able to load the original Poser file, and in some cases will crash the program!)
Now Render the file and with a bit of tweaking here and there, and a whole lot of luck, you should be able to see the seams line up when rendering in Poser.
Now with the important points lined up and "mapped" correctly it is time to draw in the basic lines that you want to have on the bump map such as collars, beading, panels, pockets, seams etc. (the wrinkles will come later.) If you load the bump map as a texture and not a bump map in Poser, updating will work better when you re-render the picture. Poser will take the updated Bitmap and render the figure with the changes.
I find using a single pixel line tool with a bright colour is the best way to map out the main lines I need.
Once the main lines are sketched in, the work on the bump map can start in earnest, but these are a few tricks that I have learned that will make you work much easier. |
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Step 4 - Making Selections
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It is always easier to have the UV map as reference when painting the bump map. This is difficult to do without destroying it when you paint over it. It is best to first create a separate layer with the UV map and then paint onto the underlying image, always keeping the UV map intact.
Here's how to do it: (Remember this is Corel Photopaint specific but this method can be adapted for Adobe Photoshop users as layers are supported in Photoshop.)
1. Use the Magic Wand mask tool - with a tolerance of 0 and anti-aliasing off - and click on the white background colour.
All the area within the templates will be masked. (I use the Mask Overlay tool to show the masked area in the default pink tone.)
2. Use the Colour Mask (Mask...Color Mask) tool to add the white areas between the UV grids to the existing mask. With the Color Mask requester open, select the Eyedropper Pick tool and click on one of the white areas between the black lines of the template. Then ensure the Smooth setting is 0. Select OK to add to the mask.
The final effect should look something like this....
3. Then with everything except the black and red lines masked, reverse the mask using the Invert Mask Tool .An an object consisting of the black and red grid lines will be masked.
4. Finally use the Copy menu item (Ctrl-C) and a Paste as New Object menu item (Ctrl-V) to add the grid as an object on top of the background. Open up the Object docker to see if your Copy...Paste operation worked.
Here is what you have done if it was possible to see it in 3-D.
Open the Object Docker (on the right margin of the Corel PhotoPaint window) and ensure that the "Background" item is highlighted (in red) and not the grid Object itself, otherwise any painting that you do will be done on the grid object and NOT on the background as you want.
The basic groundwork for all your work in now laid. I would suggest that you Save this file, just in case you want to return to it.
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Step 5 - Painting on the Map
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Now comes the interesting part.
Select the "Grid" object (the object with the UV Map lines) and change the Opacity value to around 33%.
I find this Opacity percentage will allow you to see where the bump details must be added and yet not obscure too much detail. You can always hide the grid object temporarily by clicking on the small "eye" icon in the Object Docker.
With the Background highlighted in the Objects Docker choose a large brush and choose a 50% gray as the main colour.
This will be the foundation for the bump map. Remember that a mid-gray is the middle ground for the bump mapping. Lighter tones will be rendered as high spots on the model and darker tones will render as the deeper folds and hollows. Cover all the areas within the UV template. You can go over the lines a bit. Anything outside the lines will not be included in the bump map. Be careful however not to cover too much as you could lose your reference points.
With this done, you are ready to begin creating the bump details. Firstly details such as ribbing and textile patterns can be worked in. This must be done before the folds. This is pretty much a logical thing to do because folds can be found inside the patterns on the textiles of clothes.
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Step 6 - Painting on the Map cont
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In this part of the tutorial you will be applying a strip of ribbing running down the sides of the suits and on the shoulders and arms.
1. Work out how the ribbing should look, and create a basic pattern using white lines and curves on a mid-grey background. Don't worry if it doesn't turn out right at first. Here's how the basic pattern should look and how it renders if you apply it to a flat square surface as a bump map.
With the ribbing detail finished you can now cut out and scale the basic pattern, and apply it to the UV map in the sections were you want it.
Here's how to do it...
2. It is best to draw the pattern in a New window (Ctrl-N) or on the original UV Map where there is a little bit of doodling space.
3. Use the Rectangle Mask Tool to mask out a block containing the basic pattern.
4. Copy (Ctrl-C) this masked area to the Clipboard and use the Paste... As New Object. (Ctrl-V) to paste the object repeatedly into the areas on the of the UV Map.
5. As you add objects, you will notice the object appear in the Object Docker, (if it is maximized) at the right edge of your Corel PhotoPaint 9 window. If the pattern sections that you paste start to appear above the reference grid that you set up in the previous section, then you will have to "reorder" the objects to put the "grid" object at the top of the list.
6. If the grid object is lying at the bottom of the list, click on it and drag it to the top of the list to make it sit in front of the other objects. You can see the results of reordering below.
Of course, another way of doing this is to select the grid object in the image itself and use the Ctrl-Page Up and Shift-Page-Up key combination to move the object through different layers. (Don't forget to click again on the background layer to continue to edit it afterwards.)
7. Once you have pasted all the objects and positioned them (using the arrow keys) you are now ready to "merge" them with the background. Again save the file at crucial points as it is a real hassle starting from scratch all the time should you make a mistake.
8. Use your mouse to highlight all the small pattern objects by drawing a marquee around them. (Make sure the "arrow" or Select Tool is selected to do this.)
Another way is to use the Shift or Ctrl key when selecting all the objects in the Object Docker. DON'T highlight the grid object you don't want to merge that. (Use the Ctrl Key to remove it from the selection as shown above) It is just a reference for now.
9. Now with all the pattern pieces highlighted press Ctrl and the Down Arrow on your keyboard's cursor pad to merge the objects into the background. (The same command is found in the Objects menu) Corel 8 users would use the small red icon in the Object Docker window to merge the objects with the background, or select the Objects - Combine - Combine object(s) with Background menu item.
I am sure you are dead keen to see how it is turning out, aren't you?
The best way to satisfy your curiosity is to now Import your new bump map into Poser, but you have some work to do first.
1. Save the file as it is in Corel PhotoPaint native CPT format to maintain all the layers. Once saved, right-click on the "Grid object" on the Object Docker. Choose Delete Selected Object from the popup menu that appears The grid will disappear and you will be left with the following result:
2. Now save the file as an ordinary Windows BMP file, go to Poser (you might still have Poser running) and import the picture as a texture map. Leave the bump map in Poser alone for now. You just want to see how the texture is looking.
Note: If you really want to see the bumpmap in action in Poser then you will need to load it as a bumpmap. Allow Poser to create a BUM file and set your bump height to 100% in the texture settings. (Poser and Bryce differ tremendously in their scaling of bump maps. Poser rarely shows bump details below 75%, whereas any bump map set more than 15-20% in Bryce's Materials Editor will render the bump with extreme vertical distortion which is not very desirable!)
Is your hard work starting to look something like this?
3. Return to Corel PhotoPaint and Load your picture that was saved as a Corel PhotoPaint CPT file with all the layers and objects in place. You can continue to add details like seams and surface detail to the bump map. Always use a brush with the anti-aliasing on or with a soft edge. If you draw a hard line with visible "jaggies" or pixelation, the detail will look blocky and unnatural. Remember clothing in general is soft and pliant. |
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Now comes the really challenging part - the folds!
I cannot overemphasize the need for good reference work. Search magazines and books for photographs of folds in clothing. One thing that I have learned is that folds that are not carefully (and correctly) done, look stuck on and unnatural. Try standing in front of a mirror and bend your arms, legs and torso observing how the cloth folds over certain areas and stretches smooth over other areas.
1. You will need a 2 or 3-pixel airbrush for this part. Go to the Brush Options and choose the "Small Stream" preset.
2. Now with the preset selected you can now tweak it into a "fold-creating" brush. Folds usually taper off and almost never end abruptly. Your brush settings too must fade out to the mid-gray foundation layer. Set your airbrush to fade by clicking on the Brush Settings Docker and use the settings shown at the beginning of this tutorial.
3. I would suggest saving this preset so you can use it later. Save it as Airbrush Medium Fade or something like that. Select the Brush Options tool and choose the Save brush pop-up menu option. (If this tool does not appear on your Corel PhotoPaint, you may have to install it using the Tools... Customize menu item - You can also access these commands by clicking the flyout arrow in Artistic Media Docker window.
4. Now choose pure white from the palette and start laying down the "peaks" of the folds. Don't overdo it. Remember the "valleys" will come afterwards. Use your reference to construct a realistic "network of folds. A good thing to keep in mind is the pose that you want to put your Poser figure into. Limbs with extreme bends will have more and deeper folds than normal, and straight limbs need not have too many folds. The fold lines are like a spider web connecting points of attachment.
5. Once you feel you have laid a good foundation of lines, switch to a black shade for your brush. Lay down lines between the white lines. Do not worry about them lining up exactly. The next step will fix that.
The bump map should now begin to look something like this.
6. At this stage, you might try using the Pointed Smear tool to spread the folds into more natural shapes. The tool can be found by clicking on the Effects flyout and selecting the Smear tool.
7. The default Pointed Smear is a large 20 pixel brush. Bring it down to 2 or 3 pixels for the fine work. You can work into the ribbing and seam detail that you created previously, but don't destroy too much of the detail.
The Smear has a very subtle effect but stops blobby folds!
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Now you perhaps want to keep the ribbing detail but want to smooth your folds somewhat.
Without smoothing the folds will tend to look blocky and unnatural, especially if you use them in Bryce, but with smoothing the improvement can be quite dramatic.
1. In order to do this, the ribbing detail needs to be masked out before you can soften the folds. Use the Freehand Brush Mask with the anti-aliasing switched on to create a soft edged mask. Brush in the areas you want to mask. I find the following settings to be the best.
2. You can Add and Subtract from the mask by pressing and holding in the Ctrl and Shift keys while you use the Freehand Brush Mask.
Always select the Additive or Subtractive mode setting because if you select the Normal mode it will wipe out all your previous strokes with every new stroke that you lay down. Keep the Mask Overlay button switched on to see where your mask is. It is a lot more accurate than the normal "marching ants" mask.
There we are! Almost finished! Is your mask starting to look like the first image in this step (above)?
3. Now the final step is to Invert the Mask so that the ribbing is now covered by the pink Mask Overlay colour. Don't forget to save your image!
In order to get the slopes between the peaks and the valleys of the folds smooth a slight Gaussian Blur is needed.
1. Go to the Effects...Blur...Gaussian Blur menu item and change the Blur Amount to 1 or 2 pixels. Select OK and check the results. It might be wise to go to the Objects Docker and switch the Grid object off and set the view magnification to 100%, before applying the Gaussian Blur to check the results.
You can always undo (Ctrl-Z) the Gaussian Blur if you cannot get the effect you want. (Note that the area that is masked is protected from the effects of the Gaussian Blur.)
(Tip: You can remove the mask and move in with your Pointed Smear tool to clean up any odd defects in the bump map.)
2. Save the file and then remove the grid object and save the file again as a Windows BMP file.
Now load it into Poser (or Bryce) again to see how it looks.
Add the bump map as another texture channel in Bryce and give it a 15% "strength" setting
Finally the Poser figure comes to life and his clothing, albeit a bodysuit, takes on the appearance of real clothing and not "painted on".
A high amount of detail is possible as you can see when you zoom into the face. |
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If you feel really adventurous you can experiment with the facial area and the hands as I have done with this picture. This can be a real challenge, but with carefully created wrinkle lines you can give your character real life. (Try masking off the beard area and try a faint spraypaint of a slightly lighter tone than the skin mid-gray to create some stubble. Eyebrows and eye lashes can also be rendered. I find that a single pixel airbrush on a black foundation can give the impression of the hair of the eyebrows.)
Hair is another area that can be bump mapped. It is rarely suitable for full bodied flowing hair, but ideal for close-cropped or short hair. Again reference will show you how hair flows from the crown. Experiment with everything. Try different brushes and blurring. Increase the detail by boosting the contrast or the gamma on a bump map.
With a lot of practice and experimentation you will be able to get some really spectacular results.
This tutorial has not covered how you work with UV maps in Bryce nor working with Bryce's Materials Editor. I don't intend to repeat the efforts of those experts. There are already some fine tutorials available if you want to learn more.
I have come to my final point, and that is that this tutorial is not carved in stone. I am sure there are mistakes, and places where improvements can be made. Let me know, and I will certainly try to improve it.
Happy Bumpin'!
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