'Old_2013/tutorirls & Tips'에 해당되는 글 29건

  1. 2008.10.09 Free Photorealistic Character Model & tutorial
  2. 2008.08.26 Normal Map Photography
  3. 2008.08.22 Ogre Facial Rig
  4. 2008.07.09 MAKING OF CLEP
Old_2013/tutorirls & Tips2008. 10. 9. 22:09

Article: James Busby

The following article isn't intended to be a tutorial as such but rather a focused ‘making of' during which I will attempt to explain a lot of my working practices and techniques. I'm going to illustrate this with Videos and images where appropriate. I've also included at the bottom of the article a link to the scene file, which includes a version of the scene with a frozen mesh and all the textures in JPG format at full resolution. I have no intention of discussing modeling or sculpting techniques, as there are already thousands of head modeling tutorials out there and I really don't think there is anything I can tell you that you wont find better demonstrated elsewhere. Instead I want to focus on the Texturing, Shading, Lighting, Rendering and grading of this image.

Projection Mapping

There are various ways to texture a face, a lot of people tend to use 3d paint programs such as Zbrush or Body Paint, some artists still prefer to paint straight onto the unwrapped UV layout, however I prefer to use a Projection mapping / texture-baking technique. The process involves camera projecting a reference photograph straight onto the mesh and then baking the result out to the UV map, this allows me to create a distortion free base from which I can produce my colour, spec and bump maps.

Setting up projection scene

Setting up the scene is a fairly simple process, for this project I used two cameras, one for the front and one for the side. When setting up the cameras I always try to use the longest lens possible, this helps to flatten out the features of the face and reduces texture distortion due to perspective See Images and video Below


Above Left Lightwave camera layout and settings Above Right Flash video detailing the processes involved in setting up the scene


Above: an example of what the front and side renders should look like


Now I want to show you a technique that I use to match features on a photograph to the features on your mesh without resorting to the clone tool. For this particular project I modeled the face using the photographic reference as a guide, therefore the features are approximately in the same position as those on the texture reference. However they are not exactly right so I used the “Liquify” tool in Photoshop to gently nudge the features on the photograph around until they align to those on the mesh. Take a look at the video below to see how it works



The next step in the process is to re-project the adjusted reference material back onto the mesh and bake it into two UV maps front and side which can later be combined to create a base for the colour map. In order to re project the textures I used exactly the same scene and cameras as I did to render out the front and side views. The video below shows the how the process works.


Above: Surface settings for front projection


I Set the surface of the mesh to that shown in the above image using the front facing camera to project the front image. The next step is to use Microwave to bake the front projection onto into UV map. Use the settings show in the image below and make sure you check the “Bake Colour” tab and set the Expand to 3 pixels, not including a 3-pixel border may result in visible seams around the edges of the UV maps. Also something that I've noticed with Microwave, if you don't set the resolution of the scene camera to something equal to or higher than that of the texture your baking out then it will blur the baked image. Once Microwave has done its thing and I've saved out the baked front image I then switch to the side camera apply the side projection image to the surface and run through the whole process again, not forgetting to change the projection camera to 'side' in the surface settings.


above Left : Microwave settings Above Right: Flash video depicting the reporjection process

If you don't have the microwave plug in you can use LW 9.2's new Surface baking camera. Its pretty much the same except it doesn't give you the option to bake out colour only Apply the textures using the same technique as above however make sure you set the diffuse to 0% and the luminosity too 100% this will give you a pure colour output. By this stage you should have two textures that look like something like those shown below

above Left : Baked front projection Above Right: Baked side projection

Combining baked projection maps

In order to combine the above images into a single map I loaded up the projection scene and positioned a spotlight directly down the x axis and set it to cast ray traced shadows. the purpose of this is to cast light onto only the front facing polygons. I then used Microwave to bake an illumination pass into the UV map. This gave me a black and white image where the front facing polys are white and the side facing polys are in shadow and therefore black. To combine the images I loaded both front and back maps onto individual layers in photoshop the front on top. I then loaded the baked illumination pass onto another layer and used the 'Select / Colour Range' tool to make a selection out of the black / shadowed areas of image i.e. all the side facing polygons. This selection was then used to delete the stretched side facing area of the front map. this technique is better illustrated in the video below.



Spec Removal

Removing the specular highlights is a fairly simple if not time-consuming process. I did this by creating a new layer in photoshop set to darken. Using the clone tool set to 50% opacity and sample all layers activated. I selected an area close to the highlight that I wanted to remove and cloned over the top. As you can see from the video because the layer is set to darken, only the areas lighter than those being cloned are affected. Generally specular highlights are fairly bright in comparison to the rest of the skin tone so only the small spec areas are cloned over.


Above left: Photoshop layer settings Above Right: Video demonstration of spec removal


Zbrush touch up

For this project I used Zbrush to touch up the texture map, generally this is all I use it for, I do all my displacement painting in Mudbox, I know its slower and cant handle as many polys but I prefer the interface and in my mind it's a much more user friendly piece of software. Before exporting an obj from Lightwave you should first make sure you have a map applied to face using the UV map as Lightwave doesn't export obj UV maps unless there is a texture applied to the model.

Specular Map

The spec map is in my opinion the easiest one to get very wrong, I've seen a lot of very nice models ruined by plastic looking skin due mainly to a poor spec map. I have a pretty simple way of generating the correct shades for the correct parts of the face. This is demonstrated in the Video below. Basically it involves rendering the model with a single spot light set to 100% and applying a single grey colour node to the spec channel in the node editor. I then do an FPrime render of the face and adjust the grey until I think the spec looks about right on the cheeks, which are probably the least reflective part of the face. This grey then forms the base colour for the map. Next I move onto a more oily area such as the tip of the nose. Focusing only on this area I adjust the grey again until the spec looks right, this colour can then be used to paint the end of the nose in the spec map. I repeat this process for the forehead, chin, lips, ears etc. once again its probably better illustrated with a video.

Gloss Map

In most cases I would make the gloss map in exactly the same way as I would the spec using the above process. However this is the first time I had used lightwave's node based texturing system. So I cheated a little bit by simply plugging the spec map into the gloss channel and putting a Colour Tool node in-between, this allowed me to adjust the brightness and contrast of the spec map. As a rule the more oily and reflective the skin is the tighter the highlights therefore the spec map can be used quite effectively with this technique.

Epidermal / Sub dermal

In order to use the simple skin shader node I had to make two more maps Epidermal and Sub dermal. The epidermal colour defines the skin colour without any blood. I made this by simply de-saturating the colour map. The sub dermal map should approximate the layer of fatty bloody tissue below the skin. I made this layer by adjusting the curves, increasing the saturation then blurring the image, because it only defines overall colour of the skin there is no need to have a lot of detail and things like hair follicles and eyebrows can be completely removed using the clone tool. Its also important to remember that on areas such as the bridge of the nose, chin and forehead there isn't as much fat under the skin so it might be worth going over the map with the dodge tool and de-saturating these areas slightly.

Above: Maps used with the simple skin shader

Bump Map

The Bump map is one of the easiest textures to make, assuming you have taken care when creating the colour map. Its important to get this one right, I've seen so many fantastic models ruined by terrible bump maps. The quickest way to make a bump map is to load in the colour map, de-saturate it, then use the high pass filter as shown in the video, after this use the curves tool to adjust the map until there is a decent amount of contrast between the greys. If you need to add more detail to the wrinkles you can go in as I have on this map and paint them on. I like to do this for the areas under the eyes and the lips. For the eyebrows, which are generally dark you will need to invert them. I found the best way to do this is lasso them cut them into a new layer, invert them and change the overlay to screen.



As with the modeling I don't feel its necessary to give you an in-depth rundown of my Mudboxing techniques, there are plenty of digital sculpting tutorial videos out there, and this is the first time I've ever really used it on a project so I cant really offer you anything that I'm sure a far more experienced digital sculptor could. I have however included a few videos showing the various layers in Mudbox and also the export settings that I used to get the displacement map into lightwave.


Above left: exporting model from Lightwave for Mudbox. Above right: Displacement layers and map export in Mudbox



Displacement node setup

As you can see from the video below I'm using the shader node system in LW to apply the displacement map, I did consider simply exporting the high-density mesh from Mudbox but eventually I want to animate this mesh so I really needed to keep the low res geometry.


I started this project with the intention of trying out Lightwaves node based shader system and more specifically the simple skin shader. I had done some work in the past with MISS shader in Maya and was becoming increasingly frustrated with G2's flaky performance. The Simple skin shader is very similar to MISS in Maya, its fully supported by FPrime so its really simple and easy to make changes and see them update immediately even with multiple bounce radiosity enabled. Before I start applying textures and shaders to any character model I begin by setting up the scene with a single distant light set to 100% if you can get the skin to look good with a simple lighting setup like this its only going to get better when you add some radiosity, rim and spec lights later on.


Above: Node setup as described below


This channel is used to plug the base colour map into I used a setting of about 50%. Diffuse Epidermis and Sub-dermis Visibility should add up to 100%

Respect Bump

This channel controls how much diffuse shading there is on the bump map

Specular Colour

The colour of the specular highlight, I always use a pale blue for the spec colour


Plug the Spec map into this channel. As you can see from the diagram I have placed a colour tool into the flow this allows me to adjust the brightness and contrast of the image just in case I need to fine-tune the spec later on. Don't forget that if your plugging a colour map into a scalar channel like spec then you should use a colour scalar node as show in the flow below.


For the Gloss map once again I've used a colour tool node, as I explained before I've used the same map for the gloss and spec but cheated but adjusting the brightness and contrast of the gloss until it looks correct, this is made very simple by using FPrime as you can see the updates on the rendered image almost immediately, it also saves a lot of time messing around between Photoshop and lightwave. This type of cheating is just one of the many advantages to using the node shader system. It's much better ;)


This setting allows specularity to vary according to the viewing angle of the surface, I've set it to 35%

Refraction Index

The refraction index is a measure for how much the speed of light is reduced inside the medium in this case the light traveling through the skin. The refraction index of skin is generally believed to be between 1.37 and 1.42 this shader had it set to 1.37 when I loaded it up so I just left it where it was as it seemed to work pretty well.

Epidermis Visibility

The epidermis is the colorless translucent top most layer of tissue; it allows a lot of light through to the fatty sub-dermis layer below. I've set the visibility to 30% the distance to 1.5mm, as is the default on the shader. When changing the distance settings you should always take into account the scale to which you model is made. I modeled my head to a realistic scale and as such the default settings were pretty much right from the offset. Gamma I l left at 1.0 and I changed the samples to 4, simple for speed at first but when I did some render tests I couldn't really see any difference between 4 and 8 so I left them at 4.

Subdermis Visibility

This is the relatively thick fatty bloody layer below the Epidermis it contributes quite heavily to the reddish colour of the skin as the light passes through the capillaries where the light is tinted by the blood. I've set this to 20% make the overall value of the Diffuse Epidermis and Subdermis up to 100%. Again I've left the Distance at the default 2.2mm and the gamma at 1.0 and as before changed the samples to 4.

Bump Height

The intensity of the bump map, I've increased it too 150 percent, but this value depends on how much contrast you have in your bump map the only real way to figure this one out it to do some renders and see what looks good.

Advanced / Reflection settings

By default the simple skin shader uses reflection as well as specularity, however I really didn't want to use reflection for this image. You are more than welcome to fiddle around with it and try to make it look good, but I kept getting rendering artifacts in FPrime and it was taking far too long to render out the reflection noise with multiple bounce radiosity turned on so in the end I just went for spec. If like me you decide to turn the reflections off you have to set the Mode to Spherical Map and reflection image to (none)


Lighting / Rendering / Camera Setup

This is my favourite part of the whole process it's where all the laborious modeling, texturing finally pays off. Personally I could spend days fiddling with lighting rigs and settings. For this image I wanted something that would show the face off but remain fairly gloomy and dark. I wanted him to look lost and alone. In the end I went for quite a stark contrast between light and dark keeping his entire left side in shadow. The rig is very simple, I've used one area light for the main light source and a distant light behind his head to hint at some kind of rim lighting. The rest of the illumination is provided by the background Monte Carlo radiosity, set to 3 bounces using only a grey background colour.

The camera setup is also very basic, the focal length is set to 85mm roughly around the same as most portrait photographers use. Because I'm rendering it with Fprime i don't need to worry about any of the AA settings as FPrime continually increases the quality of its AA with every pass that you leave it to do..

The image was rendered using FPrime, which is in my opinion the single greatest plugin ever invented, I can't imagine working without it. Being able to render a scene in seconds with full radiosity, reflection, SSS and displacement is unbelievably helpful when your setting up a render, it allows you to tweak until your hearts content and not have to worry about lengthy low res preview renders every time you need to see an update. If your a lightwave user I cant recommend this plugin enough. For the bulk of the rendering I use the FPrime preview but when it comes to the final render I like to use the FPrime Render plugin as it allows you to set things like lighting quality and also seems to render slightly faster and with better antialiasing than the preview.

Above left: Lighting setup and properties. Above Right Camera Settings


Post Processing / Grade

OK so using the above lighting rig and render settings I rendered out the final image which looked something like this

Above Un-Processed Render from Lightwave (FPrime)

As you can see it bears very little resemblance to the final image its going to take a lot of post work to get it there, clicking on the image below will show you an animation of the various different layers used in photoshop and Digital fusion in order to achieve the final image.


Above left: Layers Video. Above Right: Photoshop layers


Levels / curves

I always use lots of adjustment layers, for this image I really wanted to add a lot of contrast so I used an 'S' curve and crushed the backs using the levels.


I did debate using Sasquatch for the hair however this image was only ever intended as an illustration and therefore I thought it would be a waste of time fiddling with hair setting and dynamics when I could easily paint it on in photoshop.

Depth of field effect

You might notice that in the render above his ears are out of focus, I actually created this effect very simply by using the blur tool in PhotoShop. Rendering DOF in LW can significantly increase the render time

Chromatic Aberration

chromatic aberration is caused by a lens having a different refractive index for different wavelengths of light. It creates a rainbow coloured fringe where the light splits into its component colours. I really like the effect as it adds an armature photographic quality to the image. you can see its effects in the image below I've exaggerated it quite a lot in this image. I created this effect in Fusion using the Speed six Monsters Plugin 'Gun'



The grain was created very simply by creating a new layer in photoshop and applying some nice and setting the adjustment to 'Colour Burn'.


Because I rendered the character out as a 32bit TGA I was able to use the alpha map to cut him out and insert a background behind. I used an image of a hospital emergency room and blurred it in Photoshop very simple stuff really.


The final step of the grading process took place in fusion using the 'Speed 6 Monsters, Film effects' plugin which gives you the option to choose from various different film stocks, I chose to under expose this image slightly, hence the greenish tint. you can see the effects in the image below


And that's about it really, I hope this was of some use to you and if you have any questions feel free e-mail me jamie@ten24.info You can download the entire scene complete with all the maps and models from the link below. Don't forget to check out the ten24 website

Posted by DongHwan, Kim
TAG Lightwave

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Old_2013/tutorirls & Tips2008. 8. 26. 08:57

As graphics technology advances, the game artist's job becomes increasingly difficult. Modern game engines demand detailed normal maps, which can be labor-intensive to create. In this tutorial, I present a new method whereby an artist can create these maps in minutes rather than hours.

If you find this method helpful, or if you have a suggestion, let me know at richardryanclark@gmail.com.
Before beginning this tutorial, you will need the following items:

- Digital camera, preferably with a tripod.
- Computer with Adobe Photoshop, or a similar image editor.
- Movable light-source.
- Subject. (In this example, Subject is a bowl of peanuts.)
Place your camera in a fixed position, and photograph your subject four times, lighted from each of four cardinal directions, as in the examples below.

You may want to experiment with the elevation of your light. The subject should be lighted from a low angle, but not so low that it's obscured by its own shadow.
Convert your photographs to grayscale, and crop them as desired.
Create a new image, using your above-lighted photograph for a green channel, and your left-lighted photograph for a red channel.

This image will be hereafter called "Above&Left."
Open the levels dialog for "Above&Left."
Choose output levels 127 and 0, and then click OK.

Step 5:

Create a new image, using your below-lighted photograph for a green channel, and your right-lighted photograph for a red channel

This image will be hereafter called "Below&Right"
Open the levels dialog for "Below&Right."
Choose output levels 128 and 255, and then click OK.
Paste Below&Right into a new layer over Above&Left.
Set the top layer's blend mode to "Overlay," and then flatten your image.
Fill your blue channel with a light color. You may want to experiment with the shade; a lighter blue will yield a smoother normal map.
At this point, your normal map should be finished and ready for use.
If your game engine supports parallax mapping, you can use CrazyBump to create the necessary heightmap.
These renderings depict flat surfaces of two polys each.
The appearance of depth is due entirely created by photo-captured normal and displacement maps.
Direct questions and comments to richardryanclark(at)gmail(dot)com
Posted by DongHwan, Kim

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Old_2013/tutorirls & Tips2008. 8. 22. 10:54
This rig was created for the 4th DVD in the Intermediate Rigging Series from CG Academy. Two rigs were created for the DVD, the first is a blended morph driven system with a floating UI loosely based on the system outlined in the book Stop Staring by Jason Osipa.

Morph based system
Bone based system
Render of bone based system

Fifty bones were used to control the major muscle groups of the face to allow for a limitless range of motion.

The bones are controlled by two sets of controls, course and fine. The course set controls the fine as well as control each other so when the corner of the mouth is moved the cheek and other areas will move as well. This set up is circular and the controls that the corner of the mouth moved can also move the corner of the mouth. Once an over all pose is created the fine set of controls can be used to tweak shape.

The facial rig is also repurposed easily into other characters.

A screen grab of the rig reveals all the helper objects that have been used. Although this looks complex each has its purpose and is fairly simple to set up.

In the DVD I cover all the steps that are needed to recreate this rig in the Ogre character or any other type of character. Many scripted solutions are also used to speed up the process and automate some of the steps that are repeated over and over.

This is an unconstrained setup that is best used for characters were you want a very large range of motion. The animator has the ability to shape the face on any axis without reaching limits of morph targets or predefined shapes.

The main difficulty with with bone based systems is achieving realistic skin weights on the fifty bones.

Often bones need to be added to hold areas of the skin in place so that the skin doesn't deform to much.

Skin Tools has some excelent tools for blending weights together as there can be many bones affecting any one vertex. In places in this character there are up to 8 to 10 bones affect a vertex.

This is an image of the UI and character for the blended morph system. This system uses a series of morph targets and blend targets to achieve facial poses by bending many targets together at once. The control interface allows for easy control over the face with a floating UI system. There is also a pose capture system hooked up to this rig using the PEN Attribute Holder modifier found in the scripts section of this site. This method was also outlined in the book Stop Staring by Jason Osipa but is done in Maya instead of max.

Various images that were used for the promotion of the facial rigging DVD from CG Academy

Posted by DongHwan, Kim

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Old_2013/tutorirls & Tips2008. 7. 9. 08:43
Tutorial Steps:
Hello everyone! Clep is one of my latest projects and I'm gonna explain some techniques here which I used to create this image.

To create this project, I needed a basic main idea of what I wanted to show. I wanted to create a clear sense focused on one thing, that all the magic will be communicated through this object. The beginning was to make its design.

A good way to make designs is to have a lot of visual references. Use them with creativity, and start to mix things up in the mind through finding new ways to show what already exists. Our brains interpret visual stuff relating it with things that we have seen before.

Via Google, I found a lot of references to start with. It's good to save a lot of them in the PC and have them nearby as references.
Now with this, I started drawing some rough strokes. Honestly I'm not a good drawer at all, but that doesn't have to be a limitation. Anyway, it's very neccesary to have clear the ideas on a piece of paper not matter how badly they're drawn. Sometimes some stuff that works pretty well on paper may not work very well in 3D, so this could change during the process. Also you might have a change of mind or something else, so you shouldn't be afraid to make changes and try to make it better looking.

This drawing was pretty easy to do because I used a compass for all those circles.
In modeling, I try to be respectful with proportions -- they're very important as all 3D volume and esthetic depends on these proportions. The main skill of a good modeler is to be able to figure out how to build 3D models with good porportions, in organic modeling this ability could be known as having a sense of anatomy, for inorganic it could be called a good sense of geometry. This artistic eye can be developed by practicing modeling and trying to get things looking as similar to real shapes as possible. The remaining skills - the technique - is easier to get, but not less important.

I usually use the same technique to model inorganic pieces. I start with a primitive, creating a basic shape and then making the details and finally defining out hard edges -- this last note is very important. In the real world, it's dificult to see surfaces with perfect edges, even most objects made of metal don't have pefect edges. You can check this out by looking at objects around you, they have edges with a little range of smoothness, so, the best way to have this kind of edges is to create little chamfers in edges that need to be hard (this is for medium-close shots, but this doesn't apply to objects that are not too close). Obviously it's not always so easy, if the model has a subdivision like turbosmooth, you have to be careful with hard edges on curved surfaces.

Here are some modeling WIPs:
In some cases I find it useful to use booleans, some people may think booleans are the worst tool to use in modeling, but actually they're very useful to define cuts with a specific shape, cuts that will be hard to make manually, like cylindrical holes. Then I clean up the mesh by fixing the topology.
The leather belt stitches are pretty simple, I just modeled one bent cylinder, multiplicate it along the belt, and then bended them all together.
Splines are also useful to model some pipeline-looking kind of shapes, instead of extruding a cilinder it's easier to create a spline and make it renderable using its thickness value. Also it's useful to make objects that aren't like pipelines using splines. With the watch base for example, I created and extruded a spline, then added a shell modifier to it, and finally made the final details in editable poly.
Some textures like the belt were done by playing around in Photoshop with some photographs found on the Internet. The look that I wanted to get in the leather belt was very difficult to find, so I used some stone cracks and mixed them in with some leather textures.
The render was done with V-Ray 1.5 RC5 and I used its materials. Metal, transparent, fabric and plastic were the kind of materials that were used.

The metal material was done with a very dark diffuse and some reflection. Its glossines value was very useful to make it more realistic via blurring its reflections -- an amount of 12 in the subdivision value was enough to make it not too noisy. I enabled fresnel reflection and some anisotropy.
The transparent material was done with a light color, reflection with fresnel, and a lot of refraction with a bluish fog color.
The fabric materials have a fallof diffuse with Perpendicular/Parallel type, it's a fallof from the normal diffuse texture to a lighter one. I used the same, but with a higher output amount.
The plastic materials have some reflections and a suitable glossines amount.
When making lighting for this scene I thought about contrast in the lights color, it's a good way to make a rich scene, like sunsets, where the orange color of the sun makes contrast with the bluish light bounced by the sky. It was not supossed to be an exterior render, but the principle of contrast was almost the same. I created a studio setup, starting by the main vray Light, I choose the warm color for this one, a good subdivision amount for this was useful (16). Then two vray lights at the oposite side of the scene with a cold color and a small multiplier. The background was a bended plane.
This GI setup was made with consideration for the type of scene that I was going for. An Irradiance map for primay bounces to make a good result without too much rendering time, and Quasi - monte carlo (brute force in recent V-Ray versions) for secundary bounces, a good calculation method in secondary bounces for this studio scene wasn't too expensive because there wasn't too much light bounces like in interior scenes. I used a bluish color for the GI environment and an hdr image in Relection/refraction environment. I chose this hdri by making tests with several images until I found the most suitable. The lights reflection in the metal were too jagged even with a good Anti-aliasing setup, a good way to fix this was turning on the Sub-pixel mapping and Clamp output checkboxes in the Color mapping rollout.
This was the result:
The zdepth was useful to fake the depth of field in Photoshop, I could render it in the Render Elements tab. The Enable Filtering option makes the render anti-aliased and the zdepth min and max values controls the depth range.
In Photoshop I created a new channel (Alpha 1) in the render image and put the zdepth map there, I did this so that I could use it in the Lens Blur filter. The blur focal distance controls where to start blurring and the radius its intensity.
Next I added two layers to make a more interesting feeling. I used again the zdepth this time to make a little fog, obviously it's hard to see a scene like this with fog, but I found this effect quite interesting -- adding some density to the environment and more color contrast with a warm color. It was made with a brown gradient and the inverted zdepth in its alpha. The second layer was a dark surrounding halo to fill the background.
And here's the final result:
I hope you like this making of, see you next time!.

Felix Rodriguez Joleanes
email: phoelix(at)3dphoelix(dot)com
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