Creating Convincing Images with Blender Internal Renderer

In this article series by Reynante Martinez, we will learn how to go about creating really convincing still images in Blender with the help of Blender Internal Renderer.

Throughout the years that have passed since the emergence of Computer Graphics, many aspiring artists tried convincingly to recreate the real world through works of applied art, some of which include oil painting, charcoal painting, matte painting, and even the most basic ones like pastel and/or crayon drawings has already made it through the artistic universe of realism. Albeit the fact that recreating the real world is like reinventing the wheel (which some artists might argue with), it is not an easy task to involve yourself into. It takes a lot of practice, perseverance, and personality to make it through.  But one lesson I have learned from the art world is to consciously and subconsciously observe the world around you. Pay attention to details. Observe how a plant behaves at different environmental conditions, look how a paper's texture is changed when wet, or probably observe how water in a river distorts the underlying objects. These are just some of the things that you can observe around you, and there are a million more or even an infinite number of things you can observe in your lifetime.

In the advent of 3D as part of the numerous studies involved in Computer Graphics, a lot of effort has been made into developing tools and applications that emulate real-world environment.  It has become an unstated norm that the more realistic looking an image is, the greater the impact it has on viewers.  That, in turn, is partly true, but the real essence into creating stunning images is to know how it would look beautiful amidst the criteria that are present.  It is not a general requirement that all your images must look hyper realistic, you just have to know and judge how it would look good, after all that's what CG is all about.  And believe it or not, cheating the eye is an essential tool of the trade.

In 3D rendering context, there are a number of ways on how to achieve realism in your scenes, but intuitively, the use of external renderers and advanced raytracers does help a lot in the setup and makes the creation process a bit lighter as compared to manually setting up lights, shaders, etc.  But that comes at a rendering time tradeoff.  Unfortunately though, I won't be taking you to the steps on how to setup your scenes for use in external renderers, but instead I'll walk you through the steps on how to achieve slightly similar effects as to that of externals with the use of the native renderer or the internal renderer as some might call it.

Hopefully in this short article, I can describe to you numerous ways on how to achieve good-looking and realistic images with some nifty tools, workarounds from within Blender and use the Blender Internal Renderer to achieve these effects.

So, let's all get a cup of tea, a comfortable couch, and hop in!

On a nutshell, what makes an image look real?

Shading, Materials, Shadows, Textures, Transparency, Reflection, Refraction, Highlights, Contrast, Color Balance, DoF, Lens Effects, Geometry (bevels), Subtlety, Environment, Staging, Composite Nodes, Story..

Before Anything Else...

Beyond anything that will be discussed here, nothing beats a properly planned and well-imagined scene.  I cannot stress enough how important it is to begin everything with deep and careful planning.  Be it just a ball on a table or a flying scaled bear with a head of a tarsier and legs that of a mouse (?), it is very vital to plan beforehand.  Believe me, once you've planned everything right, you're almost done with your work (which I didn't believe then until I did give it a try).  And of course, with your touch of artistic flavors, a simple scene could just be the grandest one that history has ever seen.

This article, by any means, does not technically teach you how to model subjects for your scene nor does it detail the concepts behind lighting (which is an article on its own and probably beyond my knowledge) nor does it teach you “the way” to do things but instead it will lead you through a process by which you will be able to understand your scene better and the concepts behind.

I would also be leading you through a series of steps using the same scene we've setup from the beginning and hopefully by the end of the day, we could achieve something that comprises what has been discussed here so far.

I have blabbered too much already, haven't I? Yeah.  Ok, on to the real thing.

Before you begin the proceeding steps, it is a must (it really really is) to go grab your copy of Blender over at http://www.blender.org/download/get-blender/. The version I used for this tutorial is 2.49a (which should be the latest one being offered at Blender.org [as of this writing]).

Scene Setup

With every historical and memorable piece, it is a vital part of your 3d journey to setup something on your scene.  I couldn't imagine how a 3D artist could pass on a work with a blank animated scene, hyper minimal I might say. To start off, fire up Blender or your favorite 3D App for that matter and get your scene ready with your models, objects, subjects, or whatever you call them, just get them there inside your scene so we could have something to look at for now, won't we?

On the image below (finally, a graphic one!), you could see a sample scene I've setup and a quick render of the said scene.

The first image shows my scene with the model, two spheres, a plane, a lamp, and a camera. The second image shows the rendered version.

You'll notice that the image looks dull and lifeless, that is because it lacks the proper visual elements necessary for creating a convincing scene.  The current setup is all set to default, with the objects having no material data but just the premade ones set by Blender and the light’s settings set as they were by default.

Shading and Materials

To address some issues, we need to identify first what needs to be corrected.  The first thing we might want to do is to add some initial materials to the objects we have just so we could clearly distinguish their roles in the scene and to add some life to the somewhat dry set we have here.  To do so, select one object at a time and add a material. Let’s first select the main character of the scene (or any subject you wish for that matter) by clicking RMB (Right Mouse Button) on the character object, then under the Buttons Window, select Shading (F5), then click the Material Buttons tab, and click on “Add New” to add a new material to our object.

Adding a New Material

After doing so, more options will show up and this is where the real fun begins.

The only thing we’ll be doing for now is to add some basic color and shading to our objects just so we could deviate from the standard gray default.  You’ll notice on the image below that I’ve edited quite a few options.  That’s what we only want for now, let’s leave the other settings as they are and we’ll get back to it as soon as we need to.

Character Initial Material Settings

Big Sphere Initial Material Settings

Small sphere Initial Material Settings

Ground Initial Material Settings

If we do a test render now, here’s how it will look like:

Render With Colors

Still not so convincing, but somehow we managed to add a level of variety to our scene as compared to the initial render we’ve made.  Looking at the latest render we did, you’ll notice that the character with the two spheres still seem to be floating in space, creating no interaction whatsoever with the ground plane below it. Another thing would be the lack of diffuse color on some parts of the objects, thus creating a pitch black color which, as in this case, doesn’t seem to look good at all since we’re trying to achieve a well-lit, natural environment as much as possible.

A quick and easy solution to this issue would be to enable Ambient Occlusion under the World Settings tab. This will tell Blender to create a fake global illumination effect as though you have added a bunch of lights to create the occlusion.  This would be a case similar to adding a dome of spot lights, with each light having a low energy level, creating a subtle AO effect. But for the purposes of this article, we’d be settling for Ambient Occlusion since it is faster to setup and eliminates the additional need for further tweaking.

We access the AO (Ambient Occlusion) menu via the World Buttons tab under Shading (F5) menu then clicking the Amb Occ subtab.  Activate Ambient Occlusion then click on Use Falloff and edit the default strength of 1.00 to 0.70, doing so will create further diffusion on darker areas that have been hidden from the occlusion process.  Next would be to click Pixel Cache, I don’t know much technically what this does but what I know from experience is this speeds up the occlusion calculation.

Ambient Occlusion Settings

Below, you’ll see the effects of AO as applied to the scene.  Notice the subtle diffusion of color and shadows and the interaction of the objects and the plane ground through the occlusion process.  So far we’ve only used a single lamp as fill light, but later on we’ll be adding further light sources to create a better effect.

Render with Ambient Occlusion

Whew, we’ve been doing something lately, haven’t we? So far what we did was to create a scene and a render image that will give us a better view of what it’s going to look like.  Next stop, we’ll be creating a base light setup to further create shadows and better looking diffusion. Soon we go!

Lighting Setup

To setup our lights, we’d be using the effective 3-point light scheme and modify it to our liking.  As you might have already guessed, the three point light setup uses 3 light sources to properly light the scene.

These lights are :

• key light
• fill light
• back light

The Key Light will define our primary shading and it will be the strongest light in our scene and will be the source of our shadows.

The Fill Light will diffuse the shadows that the Fill Light can’t.

And finally, the Back Light will create the outline from the angle with which the camera is opposite to.

You’ll see what I mean in awhile.

Initially, we would be creating the three point light setup with three (3) spot lamps pointing at different directions.  This will ensure faster render times and lesser processing. Just so you could have an idea, the spot key light will be the only light that will create the specular highlights and shadows, and it is the strongest light. The spot fill light will only be using its energy for diffusion. And finally, the spot back light will use almost the same settings as that of the fill light, only on a different angle and a different energy level. With this in mind, we’ll try to adopt the same technique then vary them accordingly.

For our scene, we’ll use an area light to use as key light, a lamp light as fill light, and a spot light as back light.

Let’s go back to our scene and delete the single lamp light source that has been there and add our lights accordingly. Below you can see how I positioned the lights with reference to my current camera angle (this, we might change later on).

Side View

Top View

Front View

The settings of each of the lights (Area, Lamp, and Spot) can be seen below.

Key Light settings

Fill Light settings

Back Light settings

If we’d render our scene right now, it would look like this:

I’d say this is way better than the first render we did.  We now have a clear idea of the information that is being told here. Now, we know the character is standing on a platform with spheres near him that are located as well just above the ground. And clearly, we can see that the annoying blackness we’ve had before was resolved by giving it a subtle yet distinguishable diffusion.

Now why don’t we add some texture to our character now? With his current pose and state, he still looks rather boring and lifeless.  On the next part we will (as much as we could) try to give him some nice looking seamless texture.

Textures

In your journey as a 3d artist, you might have encountered several (if not all) astounding works of art.  And through close inspection, you’ll notice that we barely see them without textures.  That is because textures are one of the most important aspect of 3d, but still, this doesn’t apply to all.  But adding textures to your characters, props, environment, etc. will greatly add to the aesthetic factor of your image that you wouldn’t believe it would.

There are a number of ways to add texture to your objects in 3D such as UV mapping techniques, projections, 2D painting, etc.  All of these depend entirely on what kind of render are you trying to achieve.  But for the sake of this article, we’ll try to achieve some nice looking textures without having to worry about the complex tasks involved with it.  And with this, we’ll be using the ever famous and useful procedural textures to create seamless and continuously looking texture mapped over the surface of our models.

More information about Procedural Textures can be found onhttp://www.blender.org/development/release-logs/blender-233/procedural-textures/.

Now let’s add some textures, shall we?

Let’s select the character model in our scene then go to the Texture tab on the rightmost part of theMaterial Buttons window and click Add New to add a new texture.

Adding a New Texture

After having added a new texture, additional windows appear allowing us to further modify how the currently added texture will affect our material.  Name this first texture as “bump” and the mapping options can be seen below.

Bump Texture Mapping Settings

Bump Texture Settings

Add another texture below the “bump” texture and call it “stain”.  The settings can be seen below.

Stain Texture Mapping Settings

Stain Texture Settings

We could have added more overlaying textures, but this will do for now just so we could see how the textures have affected our material so far.  Rendering now will only lead us to the image below.

Dirtier And Better :)

This time might be a good idea to change our framing and staging so we could look at it at a better perspective.  Changing the camera angle and increasing the ground plane’s scale and some adjustments on the spheres, I achieved something like this:

New Camera Angle

For an even better interaction from within the scene, we will adjust some material settings to simulate hard and reflective surfaces.  It’s a little unfair to give our main character some good materials while neglecting the other stuff we have.  So let’s just get on, and add some decent materials as replacement to the initial materials that both the spheres have had before.

Go on and select the larger sphere and edit the current material we have so it would match that of the settings as seen in the image below.

You’ll notice I added a Color Ramp to each of the materials, this is to slightly give the color a color transition as would be seen in the natural world, in addition to the current diffuse it already has.

The vital part of the shading process of the Spheres is the reflectivity and mirror options as you can see in the following table:

                                       Ray Mirror       Freshnel

Green Sphere                 0.12                     0.76

Blue Sphere                    0.21                     0.99

 

 

Green Sphere Material Settings

Blue Sphere Material Settings

Our render would now look like this:

Reflections to Simulate Mirror Effect and Smoothness

To nearly finalize this part, we now deal with adding a texture to the world and varying the colors that would affect the Occlusion effect.

To do so, let’s first change the Horizon and Zenith color of our World and change the Ambient Occlusion diffuse energy to the color we’ve just set by changing from “Plain” to “Sky Color”, as seen below.

World Settings

Rendering now will lead us to:

New World Settings Render

Notice the subtle difference between the previous render and the latest one where the slight bluish hue is more distinguishable.

And then lastly, since we've already added some decent reflective material over to our spheres, it would be best if we can also see some environment being reflected over, to add to the already existent character as one of the objects being reflected.

To do this, we're going to add a texture to our World.  This is one nifty tool in simulating an environment since we don't have to do the hard work in manually creating the objects that are going to be reflected.  Not only does it save us a lot of time but also the ease by which we can alter these environment is already a big advantage that we have at our hands.

So to do this, let's go ahead and go to our Shading (F5) and select World Buttons.  Scroll to the far left side and you'll see tabs labeled “Texture and Input” and “Map To”, both of these tabs are essential in setting up our World texture so pay close attention to them.

Below is an image that further shows you what we need to set up (sorry for the sudden theme change).

World Texture

You might have already guessed what we should do next, if not, I'll continue on.  After heading over to the “Texture and Input” and “Map To” tabs, let's first focus on what's active by default, that is, “Texture and Input”.  In this part, we'll only need a few things to get started.  First is to click “Add New” to add a new texture datablock to our blender scene, after which, let's edit the name of our texture and name it “environment”, then change the coordinates from “View” to “AngMap” to use a 360 degree angular coordinate, you'll see why in awhile.

Adding a World Texture

After applying these initial settings, we'll go ahead and proceed to the actual texturing process, which, as far as the World is concerned is just a very quick process.  I suppose you're still on the same Buttonswindow that we're on last time.  Click on the Texture button or press F6 on your function keys. Bam! Another set of Windows.  You'll see here that the texture we named “environment” awhile back is now reflected over to one of the texture slots, just like what we previously did with texturing the character we have.  But this time, instead of choosing procedural textures like Clouds, Voronoi, Noise, etc., we'll now be dealing with an image texture, as in our case, an HDRi (High Dynamic Range Image).  Our purpose in using an HDR image is to simulate the wide range of intensity levels (brightness and darkness) that is seen in reality and apply these settings over to our world, thus reflected upon by our objects.  As in our case, we'll be using high dynamic range images as light probes which are oriented 360 degrees and that's the very reason why we chose “AngMap” as our World texture coordinate.

More info about HDRi can be seen at http://en.wikipedia.org/wiki/High_dynamic_range_imaging and you can download Light Probe Images over at Paul Debevec's collection athttp://www.debevec.org/Probes.  Save your downloaded light probe images somewhere you can easily identify them with.  I couldn't stress enough how file organization can greatly help you in your career.  You could just imagine how frustrating it is to find assets among a thousand you already have, without properly placing them in their right places, this counts for every project you have as well .

So to open up our Light Probe Image as texture to our World, click the drop down menu and choose “Image” as your texture type.  This tells Blender to use an image instead of the default procedural textures.  Then head to the far right side to locate the Image tab with a Load button on it.  Let's skip the Map Imagetab for now.

Image as Texture Type

Loading an Image Texture

Browse over at your downloaded HDR image (which should have an extension of .hdr) and confirm.  Now that the image is loaded, let's leave the default settings as they are since we wouldn't be using them that much.  You'll see on the far left Preview just how wonderful looking our image is.  But rendering your scene right now would yield to nothing but the same previous render we've had.  So if you're itching to get this image right at our scene (which I am too), go back to your World Settings and head over to the “Map To” tab just beside “Texture and Input” then deselect “Blend” and select “Hori” instead.  Kabam! Now we're all set!

World Texture Mapping options

And now, the moment we've all been eagerly waiting for, the Render! Yup, go ahead and render and it would (luckily) look like the image below.

Render with HDRi Environment

Then finally, on the next and last part of this article, we'll look on how we can even further add realism to our scene by simulating camera lenses and further enhancing the tone of the image with Composite Nodes.

Post Processing

One great thing about Blender (among the other awesome stuff it already has) is its ability to add special effects on an image or a sequence of image using post processing techniques.  Post processing is a technique or an aspect of CG or video/film to improve the quality and aesthetic portions of an image or a video footage.  Effects may include sharpening, requantization, luminance alteration, blurring, color correction, etc.

Among the hundreds of techniques that are used in post processing, for the sake of this article, we'll only be dealing with two, that is, simulating Depth of Field (DoF) and color correction.  Essentially, Depth of Field is a part of a scene, photograph, or image that appears sharp and in focus.  Beyond this distance is already blurred and out of focus.  Just like how you would see in the viewfinder of a camera when you focus on something, and the objects nearest and farthest to you look blurred.  This is an effective way of conveying your subjects to viewers, aside from toning down your colors.  With DoF, you explicitly tell your viewers to subconsciously focus their attention over to the subjects that are sharpest.

More info on Depth of field can be seen at http://en.wikipedia.org/wiki/Depth_of_field.

Luckily, there's a great tool that our great Blender has to offer. We can, however, do this process on a separate image editing application like GIMP or Photoshop or even use a dedicated application just for the simulation of Depth of Field.  But since we already have Blender, why don't we dig in and take advantage of its power for awhile?

Post processing, among other things Blender-related, can be achieved through the use of Composite Nodes.  If you are new to this thing, I suggest you head over and learn some of the basic stuff on andhttp://blenderunderground.com/2008/03/31/introduction-to-composite-nodes-part-1/.

To begin with the compositing process, let's go ahead and one of our 3D Views into a Node Editor. Do that by clicking the lower left corner of your subscreen to open up the window menus and choose “Node Editor”, as can be seen below.

Changing the 3D View to Node Editor

Doing so will show up a fresh screen with which we will be working our post processing on.  By default, this is what we should see:

Node Editor Window

This is, initially, what we don't want.  What we see now is the Material Node Editor, a special node editor for editing the material settings and for further design and alterations that the standard material editor can't.  But we're already good with the current material settings we have, so let's leave this for the meantime.  What we need to be focusing on right now is the button just beside this, the one which says “Composite Nodes”, mmmmmMmm, I already smell beauty just by saying that.

Now that you have the Composite Nodes window ready, go ahead and click “Use Nodes” and “Backdrop”. Use Nodes basically tells blender to use the nodes setup as a compositing process and backdrop is used to preview the effects of the setup on our background window (which is a very intuitive feat I might say).  Just a note, as I've had trouble figuring this out myself too before, for you to be able to see something on your background as backdrop, you must have an active Viewer selected.  If you have none, go ahead and add one by pressing Spacebar> Add > Output > Viewer and connect the image input socket to that of the output image socket you want to view.  If that looks daunting to you, we'll see how to do that in a minute.

So first things first, let's do some color correction and enhancement to the rendered image. If you don't have any rendered image in your buffer right now, go ahead and press the “Re-render this Layer” button on the Render Layer node.

Let's select the Render Layer node and press Spacebar > Add > Color > RGB Curves.  You'll notice that just by doing that, the currently added RGB Curve node is already connected to the image output socket of Render Layer and additionally the RGB Curve node is already selected, so let's head over and add another Viewer node by pressing Spacebar> Add > Output > Viewer.  This active viewer will then tell us that whatever has been done over to the RGB Curve node, it will be reflected on to here and in the backdrop.  You'll notice that the RGB Curve tool is nothing different as compared to the image processor's RGB Curves, which gives us a familiar option to tweak.  If your nodes seem a little too cluttered right now you can individually select nodes by clicking them and moving them with the G key, just like you would in the Blender 3D View.  If, however, you want to select multiple nodes, press B key for box select and click drag the node items you wish to select.  It's a good idea to get organized with your nodes because you can just imagine that if in time, you have a complete set of complex nodes, it would be very difficult and cumbersome to trace all the paths and where it leads to and from.  So it's best to start it right with organizing them depending on your preference and need.

RGB Curves node

This time, I give you all the freedom you need (I think I should have done it from the very beginning) to modify the RGB curve as you see fit.  My node setup can be seen below.

RGB Curve Node settings

Before we proceed with the next step which is adding the Depth of Field, we just need to add additional objects in our scene that will serve as our distant objects to be blurred and a very important camera setting for simulating DoF.  My current render is this:

Render with New Objects for DoF

Though we did create an initial node setup, it doesn't seem to be reflected in our render, why is that? It's because we didn't tell yet Blender to use our current node setup as a post processing procedure for our render output.  We'll get to that in a bit after we finalize setting up our nodes.

Let's go over our scene and select our Camera then go to the Editing (F9) Panel and enable “Limits”.  After just doing this, you'll notice in our 3D View that a line has been drawn from the camera suggesting the start and end of the view, and also, a yellow cross has been drawn, this, on the other hand, displays our Depth of Field clue.  In order to move the cross, go over and edit the values of the DofDist and see which fits best; just a reminder though, the yellow cross should be on the object which you choose to have the sharpest focus on.  Or alternatively, you can just type the name of your object in the DofOb field. As in my case, it's the character.

Camera DoF Settings

Now let's go back to our Node Editor and add the final node that we'll be using.  Select the RGB Curve node to make it active then press Spacebar > Add > Filter > Defocus. Then add a Viewer for this node by making the Defocus node active then press Spacebar > Add > Output > Viewer.  You'll notice that the image output socket of the RGB Curve node has been connected to the image input socket of the Defocus node, which is good, but this still lacks something of great importance, that is the Depth information with which Blender will simulate the Depth of Field.  The depth information we have right now is the Z which happens to be one of the input sockets of the Defocus Node and one of the output sockets of the Render Layer node.  So now, we'll tell Blender to use the depth information we have on our scene based on theDofDist values we added to our camera.  To do this, we simply connect the “z” output socket of ourRender Layer to that of the z input socket of our Defocus Node... And we're done? Not yet.  We have to define how much blurriness we need for our scene and how much quality would we be needed for it.

And before I forget (which I wish I didn't on some parts here), connect the image output socket of theDefocus Node to the image input socket of the Composite Node to finalize the node setup..

You can play around a bit and see which looks best.  Almost everything in the node is self-explanatory.  BUT, be sure to turn off z-buffer though, since we are using the z value in an image based processing.  Then when you're all set, you can go ahead and tell Blender to output our post processed image.  Do this by activating the “Do Composite” button found on the Scene (F10) under Render Buttons then on the “Anim” tab.

Do Composite Button

And lastly, though this is entirely optional, you can turn on Full Sampling under the Render options to further achieve an even smoother result, but with a render time tradeoff.  If you have plenty of time though and a lot of patience to wait, you can just go for it, since it doesn't hurt to have a beautiful image anyway

Full Sampling

... Leading us to this rendered image:

Final Render with DoF and Full Sampling

Bonus!

I just can't take our character looking dead all throughout our render process, so why don't we give him some nice pose so he can be remembered pretty well.

Final Render with Pose

Summary

I'm very glad you made it 'till the end of the article (which could have been very a very painstaking journey).  In this article, we learned how to setup scenes and make them look more aesthetically pleasing to the eye. Basically, we learned how to create simple-looking materials yet set them up in a fashioned way with the use of soft shadows, reflections, environment images, basic light setups, and a bit of post processing.

Hopefully next time, I could dig in more into the details of achieving high quality images using a combination of textures and how to incorporate soft body, cloth, and fluid dynamics into the scene to create a stunning realistic image.

If you have any questions, clarifications, suggestions, and/or comments, or if you just wanted to throw a note at how noisy I had been, feel free to drop me an email at reynantem@gmail.com. Please be nice, ok?