Installing SkIndigo from a RBZ file

The Indigo for SketchUp (SkIndigo) extension is available in the standard .rbz format for SketchUp extensions. These steps will describe how to install the extension.

1. Download and install Indigo

   Make sure you have Indigo Renderer or Indigo RT installed first.
   Download Indigo for your system and install Indigo to the default location on your system.
   You can download Indigo from here:
   http://www.indigorenderer.com/download/

2. Download the SkIndigo .rbz file

   If you haven't already, download the SkIndigo rbz file from the SkIndigo page

3. Install the .rbz File

   Start SketchUp.

   For SketchUp 2017 or later, select Windows > Extension Manager.

   For SketchUp 2016 or earlier,
   On Mac, select SketchUp > Preferences.
   On Windows, select Windows > Preferences.

   Select the Extensions item on the left of the Preferences dialog.

   Click on the Install Extension... button.

   Select the SkIndigo-3.x.x.rbz file you just downloaded.

   Click the Open button.

   Click the Yes button in the 'Do you trust this Extension' dialog.

   Restart SketchUp.

4. Check your installation

   Once you have restarted SketchUp, SkIndigo should be installed and available to use.

   You can check it by selecting Plugins > SkIndigo > Render Scene

Instancing

Instancing is a feature which allows many instances (or copies) of a mesh to be represented in the scene, while only actually storing the mesh once (thereby saving a lot of memory compared to straight-forward duplication).

There are two ways this can be achieved in SkIndigo:

1. Proxy Instancing

   A proxy is a reference object that references a more complex object with a usually simpler copy, in order to keep the overall scene geometry low, while allowing the render geometry to stay high.

   1. Create the object you wish to copy, create a component out of it (right click, select 'Make Component') and name it “objectname”
   2. Create a new object to use as a proxy (a cube will do) and create a component out of it named “objectname_dummy”. It is important that it has the name of the original component followed by “_dummy”
   3. Copy and manipulate these dummies around the scene and on render they will be replaced by the original component.

2. Component Instancing

   Copies of components in SketchUp will export using Indigo instances.

   1. Create the object you wish to copy, create a component out of it (right click, select 'Make Component'), with any name
   2. Copy and paste the component object.

   Component copies will be exported as Indigo instances - each component copy will only use a small amount of memory.

UV Mapping

UV mapping is the process of modifying the texture map to fit the model. SkIndigo supports 4 UV maps per mesh face, which means you can have a the texture map aligned one way, the bump a different way, and the clip map another way on every surface in your scene.

SketchUp has a basic UV positioning function that is used to manipulate the textures. It is also very important that the faces are facing the correct direction, if the UV mapping function is not listed in the Right-click SkIndigo menu, then try reversing the faces.

1. Here is an example run-through on how to set a textured object with a differently positioned bump map
2. Set the desired bump map as the albedo for positioning purposes.
3. Set the bump map position with the SketchUp tools (Rightclick > Texture > Position)
4. Rightclick > SkIndigo UV Mapping > Save UVs to set 2
5. Change the albedo to the actual albedo and the the bump to the bump.
6. Position the Albedo with the texture tools and save it as UV set 1.
   
   Selecting the UV set in the texture editor
7. In the SkIndigo Material editor, open the Texture Editor for the albedo and change the UV Set to 1. Set the bump map's UV Set to 2.
8. Now it will use different texture positions for the albedo and bump map. Render to test.

Clay Mode

If the SketchUp Face Style is set to Monochrome, SkIndigo will export the scene in Clay mode.
This is where all the materials are replaced with a grey diffuse material. This can be helpful for checking geometry and lighting without being distracted by materials.

To enable clay mode, Go to the View menu in SketchUp, then select Face Style > MonoChrome

Clay mode disabled

Clay mode enabled

Step 1. Create the basic room

First up we will model the room. Start by drawing a rectangle on the ground and another rectangle just inside it. Your rectangle should be 12 metres by 12 metres, look at the dimensions box in the bottom right of your window to see the size as you drag the box out.

The ground plan of our room

Use the push/pull tool to make the walls 3.5 metres high. We won't put a roof on the box just yet so that we can see inside it. The next step is to put a big floor-to-ceiling window at the front of our box: use the rectangle tool to draw a rectangle on the front of the box, then use the push / pool tool to push the new rectangle inwards until the wall is paper thin.

Our room with a paper thin front wall.

Now click on the paper thin wall and delete it. Don't delete the line at the top of your room, we'll need that in a second. Now press Plugins → SkIndigo → Render Scene and you will get a render like this:

Derrick standing outside his new house, in free space.

Step 2. Add window and roof

For the next step, we will add a roof and a window and set a wooden texture on the floor and a glass window. Start by using the rectangle tool to enclose the roof. Then draw a rectangle on the wall of the left hand side and use the push / pull tool to push the rectangle through to the inside. Delete the paper thin wall that is left and you should have a window hole like so:

Our box room with a window and a roof.

As a final step, use the Move tool to put Derrick somewhere side the house.

Step 3. Paint a wood texture on the floor

Next, press the Paint Bucket tool and the SketchUp materials dialog will open. Select wood from the selection box:

Now choose wood_floor_light as a texture. Then click on the floor. Your floor will now be textured, however to get a more realistic appearance for a varnished floor, we need to change the material type to Phong.

To do this, we first open up the SkIndigo Material Editor from the SkIndigo toolbar:

With the material open in the SkIndigo Material Editor, change the material type to Phong:

Zoom in the camera a little and hit render – your house should look like this:

Derrick in his new house with a roof, window and a floor.

Now right click on the floor and select Texture → Position. Rotate the wood texture 90”. You can also scale the wood texture if you want.

Step 4. Add some carpet

Carpet is a tricky thing to model because it has so many individual fibres. The best way of creating a carpet in SkIndigo is to use what is called a displacement map.

Start by drawing a rectangle on the floor and using push/pull to make it into a box of 3cm height. Then use the select tool Edit → Make Group.

When we add a displacement map, it will make our "carpet box" very bumpy, which means the edges of the box won't line up. To prevent gaps appearing, right click on the carpet and select Soften / Smooth Edges, choose a value of 90 degrees between normals and press enter.

Our carpet box ready to texture map.

Next, using the paintbrush tool, select the Carpets and Textiles set and the Carpet_Plush_Charcoal texture. Apply it to the carpet box. Right click on the carpet box and choose SkIndigo → Edit [Carpet_Plush_Charcoal]. The SkIndigo Material Editor will open:

SketchUp material editor

Note that the Albedo channel (which means the color of the material) is already set to the SketchUp carpet texture.

Now, change the displacement map to "SketchUp" which will tell SkIndigo to use the current SketchUp texture as the displacement map. Then change the value to 0.05 which will give a maximum displacement of 0.05 meters where the map pixel value is pure white. Be sure to enable displacement mapping by clicking on the checkbox.

Press Plugins → Skindigo → Render Scene, you may note that the carpet looks all triangulated and bumpy. You may need to increase the "detail" of the carpet by adding more subdivisions. Right-click the group and, from the Edit Active Mesh dialog, increase Max Subdivisions to at least 9. Also, uncheck the box for "View Dependent". This setting will decrease the amount of subdivision for geometry that is farther away from the camera, but we'll leave this optimisation for now.

Render the scene again.

Derrick admires his nice grey carpet.

Step 5. Add a chair and lamp

Use Windows → Components menu to show the components window. Search for Barcelona chair and insert one into the scene. Then search for Kare 5701 (a lamp) and insert it into the scene too.

Scene with a lamp and chair added.

In the Material Window click New Material to create a new material. Name this material "Chrome" and apply it to all of the surfaces of the lamp (Use SkIndigo → Edit [Chrome]). Then, in the SkIndigo Material Editor, change the material type to Metals, and select the Chrome preset from the dropdown box.

If you now render the scene, it should look like this:

Lamp has a shiny material applied.

Step 6. Adding nighttime lighting

Now we will try adding a lightbulb inside the lamp and taking a night scene. Start by turning off the sun by going to Plugins → SkIndigo → Render Settings, then Environment. Select SketchUp background color and make sure Black is selected like so:

Now we need to add a light inside the lamp. Double click the lamp to edit it, then look inside the lampshade and create or select the lighbulb inside it (your lamp may look slightly different, you may have to create the lightbulb yourself).

Create a new material called Lightbulb, then right click on the bulb SkIndigo → Edit [Lightbulb] material, then set the Albedo to be a constant black (since we don't want the lightbulb itself to reflect light), and set the Emission layer to 0 in the Emission section of the material editor.

Our house illuminated from a single 5000K emitter.

Step 7. Finetuning

The trick to getting really realistic renders from SketchUp + Indigo is to spend time tweaking your materials until they look just right. In this example we used models from the Google Warehouse that are relatively low in polygon count, so don't look ultra realistic, but by carefully editing the materials used on the models you can make the scene look better and better.

One of the advantages of Indigo is that if you set a 100 Watt lightbulb in a lamp, you can see how the light will fall off around the room, useful for doing lighting analysis – will you need more light fittings in the corner of the room?

To increase the realism of this scene, you could:

• Increase the Mesh Subdivision of the carpet to 10. This will make the carpet seem finer grained and more "fluffy".
• Add a bump map to the floor material, of height 0.1 centimetres, to simulate the grain of the wood.
• Reduce the "exponent" of the chrome material to make the floor lamp less reflective.

As you can see there are many options that you can tweak to get the best possible results out of Indigo.

Creating ultra realistic scenes that look like something from the real world is usually achieved by recreating all of the models in the scene with accurate geometry, and then spending 30-40% of your time modifying materials in the scene to ensure that they are as realistic as you would like them to be.

We hope you have enjoyed this brief introduction to SkIndigo.

Texture Scaling

Often you will need to change how rapidly a texture or material is repeated over a surface. This is referred to as texture scaling, or sometimes as UV-scaling.

Suppose you have a material where the texture is too 'stretched-out'.

We can fix this by changing the texture scaling.

In SketchUp, show the material dialog with Window -> Materials.

Select the material you wish to scale with the picker tool. In our case we will select the wood material on the ground object.

Click on the 'Edit' tab.

In the 'Texture' section, change the horizontal width to a smaller value, such as 0.3 m.

The texture should now repeat more rapidly over the surface, in SketchUp and in Indigo as well, when the scene is exported again.

Procedural Materials

The same technique can be used for procedural materials, which may not use a texture map. In this case, you can use a 'dummy' texture, by clicking 'Use texture image' in the Materials edit tab, and then selecting a dummy texture. The dummy texture will be displayed in the SketchUp viewport, but will not affect the Indigo render.

Modelling a pool in SketchUp

Introduction

In this tutorial I will show how to model a simple swimming pool in SketchUp and Indigo, with nice caustics at the bottom of the pool. This is what we will be making:

Model the pool ground and walls

Create a quad like so:

Create a rectangle in the middle of the quad:

Using the Push/Pull tool, push the middle down to create the pool recess:

Create the water volume

Create a cuboidal volume for the pool water. It needs to be somewhat larger than the pool recess along all axes.

Create the water material

Create a new SketchUp material called 'water' or similar.
Set the opacity to something around 50% to make sure the water material is transparent.

Apply the material to all faces of the water volume.

Move the water volume into place

Move the water volume into place with the move tool. The sides of the water volume should extend past the pool recess like so:

Finishing the water material

We need to set a couple of settings in the water material - some absorption to give the water a blue/green tint, and some displacement, to create the water ripples.

Open the SkIndigo material editor, and make sure the 'water' material is selected.

Change the material type to 'specular':

Change the Absorption type to 'none'.

Click the dotted button to the right of 'Absorption'.
Set the RGB absorption to R: 0.2, G: 0.12, B: 0.1:

Now we need to create the displacement shader.
Check the 'Displace' checkbox in the SkIndigo material editor,and set the type to 'Shader'.
Now click on the dotted button to the right of 'Displace'.
Paste the following shader code in to the shader editor:

def eval() real :
fbm(posOS() * 2.0, 2) * 0.02

Like so:

What this shader does is displace the water surface by up to 2 cm (0.02 m), based on some pseudo-random noise (fbm) based on the object-space position (posOS).
If you want to make the ripples higher, you an increase the 0.02 number.
If you want to make the ripples more closely spaced, you can increase the 2.0 number.

Setting subdivision on the water volume

We want to make sure that only the water volume mesh gets subdivided.

To do this, first make sure the entire water volume object is fully selected by triple-clicking on it:

Now right click on it, and choose 'Make Group'.

Now double-click on the group to select it. This should grey everything else out:

Now right click on the pool volume and choose 'Edit Active Mesh' from near the bottom of the menu. It should say something like 'Group#1 (6 faces)' at the top of the SkIndigo Mesh Settings dialog.

Set 'Max Subdivisions' to 8. This will turn each original quad face into 4^8 = 65536 subdivided faces.
Also un-check the 'View Dependent' checkbox, and set 'Curvature Threshold' to zero:

Make the final render

First off, we have to change the render mode to Bidirectional with MLT:

This is very important as it's the most efficient mode for rendering these kind of caustics.

Position the camera above the pool, then press the 'Render in Indigo' button.
After a while, you should get an image like this:

You may have to be a little patient waiting for the render - even with bidirectional MLT, it can still take a while.

You can download the SketchUp scene (.skp) file here.

Setting up interior lights mixed with sun+sky lighting

We will start with a kitchen scene, downloaded from the SketchUp 3d Warehouse, with some walls added:

By default this will render in Indigo with Sun+sky illumination, resulting in a render like this:

We now want to set up the lights hanging above the bench so they emit enough light to be visible.

First off, we want to add a quad in each light fixture which will emit the light.
A single quad results in the most efficient rendering. The quad should not be too small (otherwise it will make specular reflections noisier). It is also important that the front side of the quad is pointing down - as in Indigo by default, light is emitted from the front side of a surface only.

The next step is to create a new SketchUp material. I have called mine 'light mat'. Since I have the SkIndigo material editor open (you can open the SkIndigo material editor from the SkIndigo toolbar) it shows and allows me to edit the 'light mat'. You will also want to assign the your new material to the new quads you have created.

The next step is to edit your new material so it emits light.
You can do this by expanding the Emitter Attributes section, then setting the Layer to something like 1,
and setting the Emission Scale to something like 100000 lm.
Note that the emission scale needs to be very high for the light to be easily visible in daylight.

And that's all there is to it!

Since we put the interior lights on light layer 1, we can use the light layer controls in Indigo to view the contribution of the interior lights separately from the sun+sky lighting (see the layer thumbnails on the right):

Using exit portals in SketchUp

Introduction

Exit portals (often abbreviated as EP) are a way for artists to assist the rendering engine in difficult lighting situations, by specifying a "portal" through which light will travel. These are very useful for interior renders, where there is a relatively small opening letting in a lot of light (such as a window) that is not easily accessed - in such scenes, there is often a dramatic increase in convergence speed (since light-carrying paths are much more easily constructed).

In the example below both images rendered for 5 minutes, the only difference being the presence or absence of exit portals (click to enlarge):

Requirements and limitations

There are several requirements for exit portals to work effectively:

• All openings through which light can "escape" (directly to the background or environment) must be covered with exit portals.
• The exit portal normals must point inwards.
• Bi-directional path tracing mode must be used.

Finally, note that nothing gets rendered behind an exit portal: when a light ray strikes the portal it is assumed to immediately "exit" or escape to the background / environment, without considering any other objects in the scene.

Modelling with exit portals

We now show how to convert a simply modelled room with an opening into a scene using exit portals in SketchUp. The scene below shows an interior space, illuminated only by two openings which allow sunlight in:

Next we create quads to cover the openings, corner to corner. There should be no gaps, and to really make sure this is the case it could be made slightly bigger than the opening and fitted inside to slightly intersect the surrounding geometry.

The next step is crucial to stop these quads being part of the surrounding geometry (and therefore sharing its material settings): select the quads to become exit portals, right click on them, and make them a group. You should see them marked as a blue group:

To turn them into exit portals, simply use the exit portal material type for the object.

With the exit portal created, we can now export to Indigo and enjoy the much faster convergence.

If Indigo reports an error such as "Error: Scene parsing error: Model (UID 42) has a different number of materials than geometry material references", it means that the exit portal quad was merged with the surrounding objects. This won't work because we need only the quad to be flagged as an exit portal.

Make sure that the front face of your exit portal object is pointing inwards into the scene!
You may need to flip the group along an axis to achieve this.

Thanks to Filippo Scarso / Pibuz for the example scene and helpful suggestions.

Using orthographic cameras with SketchUp

Introduction

Orthographic cameras remove the perspective effects normally seen in a 3D rendered image. This is sometimes desirable for technical illustration or architectural visualisation purposes.

In this tutorial we'll cover the steps required to render with orthographic cameras in SketchUp, as well as cover some potential pitfalls with their use.

Switching from perspective to parallel projection

We start with the normal (perspective projection) camera, which will give the normal depth cues such as distant objects being smaller, in a simple scene with some boxes:

We now select the Parallel Projection option from the Camera menu, which will enable the orthographic camera mode:

With this applied, we can immediately see the viewport change to remove all perspective effects.

The zoom level may need adjusting to keep the same part of the scene in view; bear in mind that this is actually changing the camera's sensor size, so if you're rendering a building it will need a building-sized camera.

Pitfalls

Orthographic cameras require Indigo 3.4.4 or newer; earlier versions will report an error when attempting to render scenes which have a non-perspective camera defined.

The orthographic camera must be at least as large as the objects in view, since they are directly projected (parallel rays) without any perspective effects which might otherwise allow large objects in the distance to be viewed with a much smaller sensor.

One potential pitfall with large camera sensors is that they may intersect other scene geometry (e.g. go through walls), especially different media (e.g. go through glass or water), causing problems.

The former will result in open spaces between surfaces, which may or may not receive light, while the latter can be more problematic; Indigo currently (as of 3.4.8) assumes that the camera is in a single medium, which is usually a reasonable assumption, however with the large sensors sometimes used in orthographic rendering, this assumption is more likely to break down.

Using section planes in SketchUp

Introduction

Section planes allow you to create "cut-away" renders of scenes without having to change the (potentially complex) underlying geometry, using oriented planes to slice away obstructing sections from view. This is related to cut-away diagrams classically used in technical illustration.

In this tutorial we'll cover using SketchUp's section planes with Indigo version 3.4 or newer.

Adding and enabling sections

The first thing we'll need to do is enable the Sections toolbar if it is not already enabled; this can be done via the "View" menu, under "Toolbars" -> "Sections":

With these controls available, we can now add a section plane using the first tool on the toolbar (Section Plane):

Once the plane has been placed and oriented as desired, we must right-click on it and select "Enable Section Plane" from the SkIndigo sub-menu:

If we now render the scene with Indigo, we see that the section to the front of the section plane is rendered, and the rest has been clipped away:

Multiple section planes can be used together in this manner, to cut away whichever parts of the scene are obstructing an important interior view. There is no performance penalty for using one or many section planes, as they are processed at load-time; however, if a section plane intersects a complex mesh, it may require a considerable amount of extra memory to process during loading.

Pitfalls

If the section plane intersects any media in the scene, there is a chance that the medium definition will become inconsistent.

For example, if a glass pane is sliced by a section plane such that one of the sides is removed, the geometry containing the medium will be open, which can cause rendering problems.

Using the material database in SketchUp

This tutorial will cover how to download and use materials from the online material database using the SkIndigo exporter for SketchUp.

The Indigo Material Database can be found at http://www.indigorenderer.com/materials/

There are two ways to use materials from the online database in SketchUp/SkIndigo: loading directly into SketchUp, and externally linking to downloaded materials. We'll cover both options in sequence, starting with the simpler direct import method.

Importing directly into SketchUp

1. Creating a new SketchUp material

   Let's start by opening SketchUp and making a simple object to apply the material to (in this case a cube). We'll also want to create a new SketchUp material (via Window menu -> Materials -> Create Material) to hold our Indigo material, and apply it to the newly created cube.

   

2. Opening the SkIndigo online material browser

   Having created a simple object and applied a new material to it, from the "Plugins" menu, under the "SkIndigo" sub-menu, select "Material Editor":

   

   This opens the SkIndigo material editor window. At the top of the material editor window is a "Search" button, click this to open the material database window in SkIndigo:

   

3. Downloading and applying a material

   The material database browser window will open, allowing you to search for materials by keywords or name. By default the most recently materials submitted will appear at the top:

   

   If we choose a material and double click it, SkIndigo will ask if you'd like to load it into the currently selected material; click "Yes", otherwise it will want to save the downloaded material to disk.

   The downloaded material should now be loaded into the SketchUp material and applied to your object, ready for rendering with Indigo:

   

Alternative method: Linked IGM

It is however possible, that the material cannot be represented properly within SketchUp, since it is not a physically-based renderer. In such situations, SketchUp will present a warning dialog suggesting it be used as a "linked" material:

1. Linking a downloaded material

   To do this, we select the material in the SkIndigo material editor, and set its Material Type to "Linked IGM":

   

   Click the ".." button next to the "IGM" field, and select a downloaded IGM or PIGM file. This will link the downloaded material to the SketchUp material so that when Indigo renders the scene, it will use the linked material.

   Since the material cannot be represented correctly in SketchUp, SkIndigo will prompt you for a texture to use for the material in the SketchUp viewport. This is so you can easily identify the linked material, however it is optional: