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Rendering Tutorial

This is a continuation of the Coffee Mug Beginner Tutorial. The information presented here builds on the lessons learned in that tutorial. In this section you render the mug to produce a final image. If you have skipped the modeling section, you can grab the coffee mug model here. With the mug model open, make sure you're in the Model interface tab and let's get started.

It would be simple enough to just press Render and have an image of the coffee mug at this point, but it wouldn't be that interesting of an image, especially with the default settings. And while rendering a single object has its place, in most cases you render out a scene in Modo, with multiple objects, a background, and some distinct lighting. In this section we'll assign a UV map, adjust the surface of the mug and clone it, using a preset to make a basic scene, and then adjust camera and render item settings to produce pleasing results.

Making a UV Map

First, we apply a UV map for later surfacing. UV maps are a way of assigning how a flat texture gets applied to a 3D surface at render time. To make things a little easier, let's hide the handle first.

TIP:  It's not easy to avoid selecting some of the body polygons, so if you just select the main part of the handle, you can also use the grow selection (Shift+Up) to add the adjoining polygons where the handle meets the body.

Hiding geometry is a great way to concentrate on just a group of polygons in an object layer, and to ensure that geometry remains unmodified, as geometry that is hidden cannot be selected, or edited.

In the bottom sub-tab of the toolbox there are some UV tools, not as many as in the UV mapping interface tab, but enough to do what we need to do here.

This sizes the cylinder volume to match that of the selected (or in this case visible) polygons' outer bounding box volume. (A bounding box is simply a rectangular volume of space the represents an object's total height, width and depth).

Next, we'll assign an image map that matches the logo on the original reference image.

This tab has all the functions needed for laying out a scene for rendering. The Layout section is unique in that it has tools for cloning geometry, which is precisely what we are going to do next.

Before we continue, there is a rather important concept you must understand to use the tools to your best benefit. So far you've used the Polygons and Edges selection modes to modify the geometry. For laying out the scene we'll be working in Items selection mode. In this selection mode you can only modify an item's position, rotation and scale, collectively known as its transform values. The previous modes, Vertices, Edges and Polygons are collectively known as the component editing modes and are strictly for editing the geometry itself. Two distinct operations take place in either the component or Items modes, though their results are identical. Each item layer in the Item List is a container for geometry. While in Items mode, you transform the container, but while in any of the component modes, only the contents of that container can be edited.

The upper right viewport of the Layout interface has its own series of tabs and you can select the Item List tab to get a list of all the available items, or layers and they are sometimes referred to in the current scene. So, now while in Items selection mode, make sure the mug layer is selected in the Item List.

Now any operations applied to the scene only affects that selected layer.

The toolbox on the far left side of the screen has a row of buttons. Hidden underneath some of the buttons are alternate tools. These hidden tools are specified with the small gray arrow in the lower right corner of the button itself.

You might not see anything in the viewport right away, aside from a tool handle.

Eight coffee mugs appear, scattered all around. In the tools property panel, you can adjust the Count value to any number you like.

Some mugs may overlap, we fix that in the next step.

If you're not happy with the placement of the clones, you can adjust the Seed value till you receive a result you are happy with.

In addition to the original mug, you now have a number of pink wireframe clones. That pink color denotes that the duplicates are indeed Instances, virtual copies that reference the original Mesh Item. They contain no real geometry, just a reference to their originator, so they keep the scene file light and its size small. Any modifications made to the originator propagate to the clones automatically making it easy to modify them later on.

TIP:  Tumbling the viewport helps you to get a better view of the scene when making adjustments. Press Shift+A to zoom the currently selected items to fill the entire viewport, making it a little easier to navigate around amongst the multiple items.

The Item List has now gotten a little over-filled with layers, so first we need to organize it a little.

2.

Press Ctrl+G to group all the layers together into a Group Locator. Toggling the icon preceding the name hides all the layers in the list making it easier to navigate.

We need just one additional piece of geometry to fill out the scene and for that we use a Preset mesh.

This serves as the ground in our scene. It catches cast shadows, so the rendered mugs do not look like they are floating in space.

Setting Up the Render

For the rendering portion of this tutorial, switch to the Rendering interface tab. In the upper right viewport, expose the 'Shader Tree' panel, all the surfacing and render settings are set through the items in this list.

First, let's position the camera. That can be done in the main viewport area. There are three 3D Viewports to work with in the Rendering interface: the Render Preview that gives a quick reduced quality sample of the final image, the Camera view that shows exactly how the camera sees the geometry, and the advanced OpenGL Perspective view similar to the one in the Model interface.

By clicking in the upper right corner of the viewport, you can navigate around, using the standard viewport controls.

As you change the view, you can see the preview update in real time.

Surfacing the Mugs

Before we start surfacing the mug, we need to adjust the lighting, as it plays such an important role in the rendered scene. We work in a facsimile of the lighting used for the final render when adjusting surfaces. In the Shader Tree, which is the viewport panel labeled Shading found on the lower right of the 3D Viewport. It contains the various items or layers that represent the shading or rendering of our scene. Selecting one of the layers displays its attributes in the Properties panel below the Shader Tree. If it is not visible, select the Properties tab, exposing the viewport. The very top item in the Shader Tree is called the Render item. This item holds the settings related to rendering the scene, such as frame size, antialiasing and other quality related settings and also Global Illumination.

Global Illumination is a technique used in 3D graphics to mimic the effects of real world light bouncing around in a scene, producing extremely realistic results. It is such a common technique to use, it is turned on by default in a new scene.

To toggle this setting, while the Render item is selected in the Shader Tree, under the Properties tab, select the Global Illumination sub-tab.

Check or uncheck the box next to Indirect Illumination.

When enabling Global Illumination, Modo lights the scene using the settings of the Environment Item. By default, this comes from a gradient applied to the Environment Material.

If you prefer the look of Image Based Lighting, add an HDRI environment. This can be done easily using the presets Modo provides.

The lighting dramatically changes for the scene in the Render Preview producing a nice outdoor look to the rendered image.

The lighting in the Beverly Hills image is coming from the right-hand side for our image (-X), so let's rotate the Directional Light to match that. This can be best accomplished in the Perspective view across the bottom.

This allows you to easily rotate the light from the world's center.

The next part is surfacing. Earlier in the modeling tutorial, a Material tag was applied to the model, named 'Mug'. This action also created what is called a Material Group. This particular item creates a procedural mask that limits any surfacing contained under that group in the Shader Tree to just surfaces tagged with that name. For more details about this, see the Shader Tree section. Each Material Group mask contains a Material item that controls most of the attributes of any surface, such as color and luminosity. We need to select this item to edit it in the Properties panel. While it's easy to select the proper Material item in the Shader Tree in this case, Modo allows you to quickly see what layers are attributed to any part of the scene, by using a shortcut in the Preview viewport.

Looking over the attributes in the Properties viewport, we need to adjust the color, as it is much lighter than the mug in the original image.

This softens the overall sheen, looking more like the original matte surface.

You can see now its much closer to the original mug.

NOTE:  These attributes are render intensive, so if your system specifications are modest, keep them at the default disabled state. For more information on them, see Material.

Next, we utilize the UV map we made earlier to apply an image to the mug. Grab this image of a Modo logo and save it, so you can apply it to the model.

The image appears right away on the surface.

If the image does not show up correctly, it is probably not assigned to the UV map properly.

This controls how the image maps onto the mug surface.

The image we just applied is a transparent .png. Because of the layered approach of the Shader Tree, the transparent edges show the regular material color underneath our image instead of making the surface transparent. This makes it easy to add labels, markings and other non-rectangular images to a surface.

One problem is that the inside of the mug has a logo as well. Since the mug is one continuous surface, the logo projects all the way into it. The easiest way to remove the unwanted logo is to apply a different surface to the interior of the mug. This is where it turns into a good idea to have cloned using Instances, any changes made to the original now propagate to all the clones.

You can see in the Preview that the insides of all the mugs are now back to the default values, but the logo is gone. The inside material has to match that of the exterior. It is useful to instance the material, so that changes to it also change the instance later on if you need to edit them:

There are now two Material items in the group, one of them has its name italicized.

Click on the italicized one and drag and drop it above the material inside the Inside Mug group.

Click to select the Material that was already in there and press Delete, to remove it from the tree as it is no longer necessary.

Now the insides have no logo, the inside surface matches the exterior and since the interior mask contains an instance, any changes made to the original propagate to the instances, so subsequent edits effectively change both surfaces.

You can see your progress by pressing F9 to render the scene. Feel free to make adjustments to the Shader Tree to get a feel for what does what. Once you have the scene the way you like it, make sure to save it. Here is mine:

You can add some more effects to make your scene even more realistic.

NOTE:  Some of these settings may take a long time to render, so if your machine specifications are modest, or you don't like waiting for renders to complete, skip these steps.

The first settings you can adjust are those of the light. The shadow the mugs cast are a little harsh.

For the Camera, select the Camera item in the Shader Tree so you can edit its attributes. The shallow depth of field look is very popular, so let's enable that feature also.

You can also select the Autofocus button, this causes Modo to fire a single ray from the center of the camera and set the Focal Distance at the first surface it encounters.

This tutorial has given you an overview of working from start to finish in Modo, and the steps that are required to complete a project including setting up the scene, the difference between the component and Items selection modes and how to enable and use Modo's Global Illumination rendering engine. If you'd like to explore further, you can assign some preset surfaces to the Ground Plane, select a material in the Preset Browser and drag-and-drop it somewhere in the 3D Viewport and drop it onto the Ground Plane.

If the image looks too grainy for you, you can increase the Antialiasing level in the Render Item under the Settings sub-tab. For the Soft Reflections and Soft Shadow options of the Material and Light items respectively, increasing the Samples values can also help. Keep in mind that as the number of samples increase, image quality increases, but so does the render time.