Adding Realism to Rendered Scenes

What if your scene doesn’t look realistic enough? Or what if it doesn’t match the reference image completely? What can be done to improve the scene appearance? This tutorial shows some tricks that may improve your scene look easily.

A Bit Of Theory

There are two things that affect result in Boxshot: ´╗┐materials and environment. Materials are quite obvious - they have colors, textures and various parameters including the reflection ones. Even if material is diffuse (matte) it still reflects, but reflection is so blurry, you can’t really see anything but the overall color of the environment.

Let’s put a simple matte bottle into an empty scene:

Matte white bottle on white background

You see that some areas are white and some are gray, why that? Because of the default environment map used by Boxshot. You can see it by switching the background mode to “Environment”:

Enabling environment background mode in Boxshot

Now you can see what lights up the scene, so we are ready to start.

Materials

In this tutorial we’ll focus on opaque plastic materials, leaving metals and translucent materials aside. We will adjust the properties of the bottle cap to make it look better and the first thing we’re going to do is to change its diffuse color for better visibility. You don’t have to do that and if your cap is white, you are free to leave it as is for now. For this tutorial we’ll make it orange:

Making bottle cap orange by changing its diffuse tint in Boxshot

That’s better, we can see where the cap is and where the background is, but the cap itself still looks “flat”. That’s because the lack of reflection.

In real life plastics reflect. Even the matte ones. The reflection depends on the physical property of the plastic called “index of refraction” or simply “IOR”. Most of plastics have it about 1.5. Let’s set that:

Setting index of refraction to 1.5 in Boxshot

Great, we’ve got reflections or (in our case) highlights. The reason is that the plastic here is rough and provides blurred reflection. We can change that by using the Roughness parameter:

Setting roughness to 0 in Boxshot

Now we can clearly see the environment reflected in the cap. Great, what you can also do is to tint these reflections up to make them not so white. This goes against the physics (as plastics have white reflection) and adds a metallic look, so use with caution:

Using reflection tint in Boxshot

That’s basically all you need to know about opaque plastic materials to make them look realistic. But that is just a half of the story, as we still have…

Environment

As we mentioned above, the scene is surrounded by environment. As in real life, there is always something around any object. If you take photos in a studio, there will be background, lights and so on. If you are outside, there will be grass and sky, maybe the sun or clouds. Environment does a very important job: it provides the light to the scene. Without that light the scene would be dark and we get just a black screen rendered. Not good.

So how do we simulate environment in rendering software? We can add some objects and lights here or there, but that is way too long and complicated. Instead, we use environment images (or maps, or textures) that have all that information baked-in. Boxshot comes with some built-in environment maps that you can find in the Assets panel. Lets drop one into the scene:

Loading a different environment map image in Boxshot

This changes the scene completely! Note that neither the camera, nor shape or material have been changed - we simply loaded a different environment image and the materials picked it up.

By this time you have probably realized that environment image is the key to a realistic scene appearance. It provides both lighting and reflection information to the renderer and if you want a realistic rendering, you will most likely spend some time configuring the environment.

Note that you are not limited by the environment maps in the Assets panel. You can use virtually any image as environment, but for good results the images need to be in hight-definition range (HDR), so they provide enough light to the scene. Here I used a completely different HDR image for the same scene (no other changes made):

Loading a third-party environment map image in Boxshot

Again, you can see our white bottle picks up blue tints of the environment. There are plenty of HDR environment maps in various photo stocks, so try to find something that makes the look you need. You can also edit those images in Photoshop to add some highlights or shadows to the scene where needed. Just make sure you save to HDR-supporting formats (EXR is the best) and use bright colors (with intensity 2 or more) so the environment map emits enough light to the scene.

Finally, you can fine-tune the scene by moving highlights or reflections along the shape. To do so, adjust the horizontal rotation of the environment map. For instance, here is the original scene:

Default environment map image in Boxshot

And here is the same scene with environment map rotated a bit:

Rotating environment map image in Boxshot

As you may see, reflections and highlights have moved along the shape with the environment image in background. Rotate the environment image to place the highlights where they look better. If a highlight is missed somewhere, you can always add it to the environment map in Photoshop.

Too Much Light?

Sometimes a scene may look way too bright even if the only light source is the environment map. There are two things you can do about this:

Well, that is obvious as everything you see in the scene is a combination of those two items. Lets have a look at the image above, especially at the bottle itself. It is too white, so the shape is not clearly visible. The cap is fine, so we’d better adjust the material as adjusting environment will affect everything in the scene. What we can do is to make the diffuse tint of the bottle light gray instead of white:

Making a bottle not so white with diffuse tint in Boxshot

Now you can see the bottle itself more clearly. You can do the same by adjusting environment intensity:

Making a bottle not so white with environment intensity in Boxshot

Again, we’ve got a not-so-white bottle, but the cap is also darker. Decide for yourself which option gives better results and use that one. Or both.

Background Mode Doesn’t Matter

Of course, you don’t have to keep the environment map visible at background if you don’t want to. This tutorial shows it so you can see what exactly lights the scene, but you can set background to a solid color or transparent mode without affecting the scene look:

Using white background in Boxshot

Note that the shape itself looks exactly the same. It is only the background that was changed.

Once Again…

So here is a simple list of the things you need to consider to get a better appearance of the scene:

This works for any type of materials, not only plastics. The details may differ, but the main idea is the same: everything is controlled by materials and environment.

That’s All!

It takes some time to get used to environment maps, but once done you’ll hardly look back :)

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