Rhino #3: Rendering Test Images

Rendering is a process where a 3D software package outputs images. Calculating these images usually takes a lot of time, so here's how to do quick test renders that you will use while setting up lighting and materials.

Scene Set Up

Ideally, please use the Rhino file you’ve been working on previous Rhino tutorials:

Rhino #1: Scene Organization And View ControlBefore we dive deeper into rendering digital images with Rhino, we need to cover basics of organising the scene successfully.


Rhino #2: Setting Up The ViewsCamera control is one of the essential parts of creating impactful architectural images. Here's a complete guide on how to control the camera and views in Rhino.


If you didn’t finish these tutorials (which I strongly suggest you do), you can download the tutorial #2 “finished” Rhino file and start working from there:

Download Rhino Scene: Barcelona Pavillion with defined views. ( 3,9Mb .zip)

 

What Is Rendering?

Rendering is a process where a 3D software package creates an image out of your model. That model can be photorealistic, or stylized – all depending on parameters that you set, such as lights and material properties.

There are two ways to do that in Rhino:

Capture View To Image File

This is the simplest way to create an image is to capture exactly what you see in view (on screen) – you save exactly what you see in the viewport as an image file.

To capture the view in file, click the view menu and then select Capture > To File.

1-capture

You will be asked for a file name and location. Let’s save this as a statue_capture.jpg.

If we open that file in Photoshop, we’ll see that the resulting image is not quite big – you will have different image size depending on your screen resolution, tough – in my case it was 918×543 pixels:

1-capt2

If we wanted to print this at 150DPI, the maximum print size we could get would be some:

918 /150 = 6,12 inches (about 15.5cm) width and
543/150  = 3,62 inches (about 9.2cm) height.

This maybe enough for what we need, but very often we’ll need a higher resolution output than what we can get from our screen.

Capture at Higher Resolution

To do this, we need to write down manually the command -ViewCaptureToFile.
Please note that it begins with “-” sign: this will let Rhino know we want additional options.

  1. Type -ViewCaptureToFile in the Rhino command line.
  2. Type b then press enter to Browse for the filename/location (as in previous example). Let’s call the new file statue_capture_big.jpg.
  3. Now you will see a lot of options. You will also see what the width/height of the image is (918×543).
    Click the Scale, and enter number 3. This will multiply the screen resolution by 3.
  4. Press enter again to finish the command.

Important: Never write down width and height manually (although it IS an option) because it can cause some problems with export due to a Rhino bug. Always use Scale instead.

1-captscaleHere’s the log of what we’ve done: 

Now if we open the new image in Photoshop, we’ll see we exported a much bigger image (exactly 3 times the width and height):

1-captbig

Capture Transparent Images

In order to capture the transparent images (with no background, in this case: just lines), when you are browsing for file name and location, select an image file format that supports transparency (for example, PNG) and then check the Transparent Background option:

1[ca;

Then in Photoshop you’ll get a line drawing with transparent background:

1-transp

Important: If you keep the Transparent Background checked, but then select a file format that doesn’t support transparency, you will get a black image. So now, if you suddenly get black image, you know why. Uncheck the Transparent Background (if you want to use JPG), or use PNG instead.

Changing Display Options

You can also change how the view looks in the Rhino directly, just look for Display panel.
You can change a lot – let’s try and change the background from the “paper texture” to solid yellow (gold) color, for example:

1-yelo

Play with other options below to see how this affects the display of the model.

Use Renderer

View capture is good enough for some cases, but most often we will want to use renderer.
Renderer will perform complex calculations in order to create an image based on your geometry, lights, materials and special effects, and it can take a very long time, depending on complexity of your scene.

We will be using Rhino’s built-in renderer, which is not very good (at all), but it’s good enough to get us started, and make solid images (when we do post-production in Photoshop). If you need a very realistic looking images for professional presentation, you will have to use some rendering plugins, such as VRay, Brazil or Maxwell. There are a lot of more plugins.

Let’s just try and render this view.

Open Render Tools Tab, then click the first icon (Render):

1-render

You will get a very basic rendering, similar to this one. You can always click on a disk icon to save the rendered image to file.

1-render2

So this was quite fast, but the result is not very good. Most of the scene is in the dark, and there is some random shadow coming from default light (default light is active when no other light is present in the scene).

Use Rendering Preview For Quick Test

Exactly like it says. Preview (second icon) will render in low resolution giving us much quicker feedback. We usually almost always want to render previews unless we have some special reason to render high resolution image (like for, obviously, final rendering, or to check details).

preview

 

 

 

Any questions?

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