MAXON Cinema 4D R20: A Detailed Guide to Texturing, Lighting, and Rendering

By Pradeep Mamgain

The MAXON Cinema 4D R20: A Detailed Guide to Texturing, Lighting, and Rendering book walks you through every step of texturing, lighting, and rendering projects in Cinema 4D. This comprehensive guide caters to the novices and intermediate users of Cinema 4D. This book will help you to get started with texturing, lighting, and rendering in Cinema 4D, you will learn important concepts and techniques about rendering which you can utilize to create high quality renders.

Using a structured and pragmatic approach, this guide begins with basics of rendering, then builds on this knowledge using practical examples to enhance your texturing and lighting skills. Each unit builds on the knowledge gained in the previous unit, showing you all the essentials of rendering with Cinema 4D, from sampling to shaders, maps, camera effects, post effects, and lights. As you go from hands-on exercise to hands-on exercise, you'll develop a strong arsenal of skills that combined will form a complete end to end process to creating high quality renders using the Standard, Physical, and OpenGL renderers. You will also learn about the new node-based material system in Cinema 4D.

For more info, visit Padexi Academy's website.

• Language: English
• Publisher: Pradeep Mamgain
• Release date: Mar 25, 2019
• ISBN: 9781386123583

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Unit CR1: Standard Renderer

The Standard renderer is the default renderer in Cinema 4D. In most cases, you can use this renderer as it is fast and stable. However, if you want to render special effects such as depth-off-field and motion blur, use the Physical renderer. This renderer and other built-in renderers available in Cinema 4D are discussed in later units.

Exploring Render Settings Window

The settings for the Standard renderer can be accessed from the Render Settings window [see Fig. 1]. To open this window, choose Edit Render Settings from the Render menu or press Ctrl+B. Alternatively, you can click the Edit Render Settings button in the Standard palette > Render command group. You can also access these settings from the Attribute Manager [see Fig. 2]. To do so, select Mode > Render Settings from the Attribute Manager's menubar.

The Render Settings window is divided into two panes. The left pane contains a list of render options. When you select a render option from the left pane, the corresponding settings are displayed in the right pane. The post and multi-pass effects can be added by clicking on the Effect and Multi-Pass buttons, respectively. A check box is available on the left of most of the post effects and multi-pass effects options. You can use this check box to enable or disable the corresponding option. If the Standard renderer is not selected by default, you can select it from the Renderer drop-down list available on the top-left corner of the Render Settings window.

When you select an option from the left pane of the window, the corresponding options that you can modify will be displayed in the right pane. If you modify an option in the right pane, the corresponding label will be shown in black and in bold face because these values differ from default values. Let's explore the commonly used rendering options available in the left pane of the Render Settings window.

Output

The Output settings only affect the rendering in the separate render window. These settings do not affect the rendering in the viewport. At the top-left corner, an Arrow button is available. Clicking on this button reveals the commonly used resolution settings for print, video, and films. For example, if you want to use the HDV 1440x1080 resolution, click on the Arrow button and then choose Film/Video > HDV 1080 25 or HDV 1080 25 option.

The Width and Height parameters define the width and height of the image, respectively. The drop-down list on the right of the Width parameter is used to select the unit of measure. By default, the Pixels option is active. When you select a preset, it automatically sets the other settings such as resolution, aspect ratio, frame rate, and so on. The Lock Ratio check box allows you to adjust the width or height of the image automatically if one or the other is modified.

If you are rendering a video and want to define a bit rate for it, ensure the Adapt Data Rate check box is selected and then select the Save render option from the left pane. In the right pane, select a video format such as MP4 from the Format drop-down list. Next, expand the Format area and then define a bit rate using the Data Rate (kBit) parameter [see Fig. 3]. You can expand the area by clicking the triangle located on the left of the Format label.

The Resolution setting does not apply to video but if you are rendering an image for the print, you can specify a DPI value using this setting.

If you have a made a minor modification in the scene that just affects a smaller area, you can render a small region instead of whole image. The Render Region function allows you to render a selected region of the scene. To define a region, expand the Render Region area and then define the region using the Left Border, Top Border, Right Border, and Bottom Border parameters [see Figs. 4 and 5]. In Fig. 5, I have specified values 50, 50, 100, and 100 for the Left Border, Top Border, Right Border, and Bottom Border parameters, respectively.

Tip: Copying settings from IRR

If you have defined an interactive render region in the viewport, you can quickly specify the values of the Left Border, Top Border, Right Border, and Bottom Border parameters by clicking on the Copy from IRR button; Cinema 4D will fill values for these parameters using the dimensions specified using IRR.

The Film Aspect parameter reflects the X:Y ratio of the file to be rendered whereas the Pixel Aspect parameter defines the on-screen-width:on-screen-height ratio of a pixel. The pixel aspect ratio for most of the monitors is 1:1. The Frame Rate parameter sets the frame rate for the render.

The options in the Frame Range drop-down list allow you select the frame or frame range to be rendered. Once you select an option form this drop-down list, the From and To parameters reflect the corresponding frame numbers. If you want to skip frames while rendering, you can use the Frame Step parameter. For example, if you setup this parameter to 5 for test renders, only every 5th frame will be rendered offering a rough estimation of the final output.

Save

The Save settings allow you to save an image, a video, or sequence of images to the Picture Viewer window. There are two areas available in the right pane: Regular Image and Compositing Project File. These areas are discussed next:

Regular Image

The File parameter is used to specify the path where you want to save the files. If you specify a file name without path, the image or image sequence will be saved in the active scene's folder. If you want to use relative paths, place periods at the beginning of the path name.

Create a folder with the name path and then create sub-folder with the name x. Now, save the scene with the name test.c4d inside the x folder. Create a folder with the name y inside the x folder. Now, specify path as ./y/diffuse and then press Shift+R to render the scene; the rendered image with the name diffuse will be saved in the path > y folder. Because, when we use a single dot [.] in the path name, it refers to the absolute path. You can use two dots [..] to specify a relative path from the location at which the scene file is saved. Now, if you specify ../diffuse as path, the control jumps one level up in the directory from the location [file is saved in the x folder] at which the scene file is saved. As a result, the file with the name diffuse will be saved in the parent folder path.

Caution: File name

The maximum length of the filename is 22 characters. Out of 22, 4 characters are reserved for the file extension [for example .png] and 5 characters are saved for numbering frame sequences [for example _0025]. Also, you can use only the following characters in the file name: A - Z, a- z, 0-9, _.

Tokens

You can use variable path and file names known as Tokens in the File input field. Tokens are simple text variables, when they are rendered or displayed in the Picture Viewer window, they will be replaced by parameters such as name of the project, the current camera, take, and so on. The following tokens are available:

$prj: Project file name

$camera: Current camera name

$take: Current take name

$pass: Multi-pass or object channel name [the defined multi-pass names].Primarily to be used as directory name.

$userpass: Multi-pass or object channel name. Primarily to be used as a directory name.

$frame: Current animation frame

$rs: Current render setting name

$res: Image resolution (e.g., 800*600: 800X600)

$range: Animation range (e.g., from frame 23 to 76; 23_76)

$fps: Frame rate

You can type these tokens or you can click on the arrow button corresponding to the File parameter to open a flyout and then select desired option from the flyout.

Create a folder with the name tktest in your system. Open the tokens-start.c4d file. Now, in the Render Settings window, specify path for the folder tktest. Now, append a \ at the end of the path and then choose Current Camera from the Tokens flyout; Cinema 4D shows the new path: .\tktest\$camera. Now, append a \ at the end of the path and then choose Render Settings from the Tokens flyout; the new path will be displayed as follows: \tktest\$camera\$rs. Add a \ at the end then type tk-seq as the file name. The complete path should now read like follows: .\tktest\$camera\$rs\tk-seq.

Notice in the Object Manager, RN_CAM is the name of the camera. Also, notice in the Render Settings window, the name of the active render settings is Low Res. Now, press SHIFT+R to render the sequence. Now, navigate to the tktest folder and then check the directory structure [see Fig. 6]. Also, see tokens-finish.c4d.

The options in the Format drop-down list are use to select the file format for the image or image sequence. If you expand the Format area, the Presets drop-down list will be revealed. It contains options [if available] for the format you selected from the Format drop-down list.

For example, if you select WMV from the Format drop-down list, you will notice that there are some presets available for the selected format. Below the Presets area is the Options area from where you can set various parameters for the selected parameters.

The Depth parameter defines the bit depth per channel of the image. You can select the 8 Bit/Channel, 16 Bit/Channel, or 32 Bit/Channel option from the Depth drop-down list. These options are used for 24-bit color, 48-bit color, and 98-bit color, respectively.

The options in the Name drop-down list are used for sequential numbering of the image files. The letters TIF represent the extension of the selected file format such as JPG. For example, if you select JPG as file format and beauty as filename:

Name0000.TIF will result in beauty1234.JPG

Name0000 will result in beauty1234

Name.0000 will result in beauty.1234

Name000.TIF will result in beauty123.JPG

Name000 will result in beauty123

Name.000 will result in beauty.123

You can use the Image Color Profile setting to define which color profile should be embedded in the rendered image.

Tip: Color profile

If you are using the Linear color profile [for example with the HDR format] with multi-pass feature, it is recommended that you render images with the 16-bit color depth because multi-passes are saved with the Linear color profile. When the color profile management is disabled, no color profile will be embedded in the rendered images. Expand the Image Color Profile area; a big vertical arrow button will be revealed on the right. Click on this button to view options for selecting color profiles.

Caution: Color profile

Many of the programs can't read color profiles. For example, Windows 7 partially reads profiles. Generally, the default sRGB profile will be the correct profile.

Select the Alpha Channel check box to calculate a pre-multiplied alpha channel. The alpha channel is the grayscale image of the same resolution as the color image. The white pixels in the alpha channel indicate the presence of the object whereas the black pixels indicate there is no object. You can use the alpha channel to composite two images. The image at the top can be blended with the image underneath using the alpha channel. If the alpha value is white [opaque], the top color overwrites the destination color, if black [transparent], the color at the top is not visible. As a result, allowing the background to show through.

Note: Pre-multiplied alpha

When you render an image with pre-multiplied alpha, the alpha channel picture is antialiased to ensure a soft transition in the composited picture.

When the color channel and alpha are multiplied, the alpha channel causes a dark seam because both the color and alpha channels are rendered with antialiasing and black is multiplied twice. If you want to avoid the dark seam, select the Straight Alpha check box.

Caution: Straight alpha

Straight alphas are only suitable for compositing images only, they are not useful for the conventional images.

Usually, the alpha channels are integrated into those image formats which are alpha channel capable. In other words, they are saved with the color image. If you want to save the alpha channel as a separate image, select the Separate Alpha check box. The alpha channel files are saved in the same format as the color files.

The 8 Bit Dithering check box is used to add a random patterns to the colors to prevent color banding. Enabling dithering enhances image quality but also increases the file size. Therefore, it is not recommended to be used if you are rendering web graphics.

If you select one of the video formats from the Format drop-down list, select the Include Sound check box to integrate a sound file into the video.

Note: Bitrate for videos

The term bitrate refers to the number of bits that are processed in a unit of time. Remember that 1 byte consists of 8 bits. Video data rates are given in bits/second. The data rate for a video file is the bitrate. In Cinema 4D, you can define bitrate for both audio and video. To do so, expand the Format area and then in the Options area you can define bitrate for video and audio by using the Data Rate (kBit) and Audio Bitrate (kBit) options, respectively.

Multi-Pass Image

If you enable the Multi-Pass render option, you will have access to the Multi-Pass Image area [see Fig. 7]. By default, the Multi-Layer File check box is selected. As a result, all layers are saved in a multi-layer file such as a Photoshop [PSD], BodyPaint [B3D], or TIFF file. Also, Cinema 4D creates a separate file for each pass and suffix is added to each of the filenames to differentiate them.

If you have chosen a format from the Format drop-down list that does not support multi-layers, each layer will be saved as separate file. If the Layer Name as Suffix check box is selected, the name of the layer [for example, _diffuse, _reflection, and so on] will be added after the filenames.

Each multi-pass has its default name such as Ambient, Diffuse, and so on. If you want to use your own names, double-click on the pass name in the left pane of the Render Settings window and then type a new name. Next, select the User Defined Layer Name check box. Now, the user defined names will be used for passes instead of the default ones.

Compositing Project File

The options in this area [see Fig. 8] are used to create a compositing file made up of multiple layers. Each layer can be edited separately. You can select the application for the project from the Target Application drop-down list. The available options are: After Effects, Nuke, Motion, and Digital Fusion.

Anti-Aliasing

The settings corresponding to the Anti-Aliasing option allow you to remove jagged edges from your images. The process works by first breaking down each pixel into sub-pixels and then calculating and averaging several color values to produce the final color for the pixel. The commonly used options are discussed next.

The default method is Geometry which smooths all object edges using a 16x16 sub-pixels. Figs. 9 and 10 show the render with Anti-Aliasing set to None and Geometry, respectively.

The Best method uses additional sub-pixels and Cinema 4D's adaptive antialiasing. The adaptive antialiasing is enabled for those pixels whose value substantially differs from the its neighboring pixels. It also affects the color edges as well as the objects behind transparencies.

The Min Level parameter defines the minimum number of sub-pixels that will always be rendered. The default value 1x1 is suffice in most of the cases. However, if you see some artifacts such as swelling of the shadows, a higher value should be used.

The Max Level parameter defines the sub-pixel dispersion that will be applied to the critical region such as the high contrast region, for example, color edges and object edges behind the transparencies. The default value 2x2 is suffice in most of the cases. The higher the value you specify, the more the render time will be.

The Threshold value can be used to specify the degree of color divergence at which the Max Level value should be applied for a given pixel. Figs. 11 and 12 show the render output when Anti-Aliasing set to Best and the Max Level set to 2x2 and 8x8, respectively. Also, refer to anti-aliasing.c4d.

Options

The Options settings are to used to define various parameters that affect the rendering. These settings are discussed next:

Transparency

Use the Transparency check box to define whether or not Transparency or Alpha channel should be included in the render calculations. By default, this check box is selected. Fig. 13 show the rendered output when Transparency, Refraction, Reflection, and Shadow are enabled. Fig. 14 shows the output when Transparency is disabled. See the rays.c4d file for reference.

Refraction

Use the Refraction check box to define whether or not the refraction index should be included in the render calculations for the transparent materials. By default, this check box is selected. Compare Figs. 13 and 15. Fig. 15 shows the output when Refraction is disabled.

Note: Refraction index

Materials such as glass and water look realistic when they are rendered with refraction index but they increase the render time as well. However, note that if the scene does not contain materials that reflect light, no additional render time will be added if the Refraction check box is selected.

Tip: Rendering transparency

If the transparent objects that lie behind other transparent objects are rendered black, increase the value of the Ray Depth parameter. The default value for the Ray Depth parameter is 15.

Reflection

Use the Reflection check box to define whether or not reflection should be included in the render calculations. By default, this check box is selected. Compare Figs. 13 and 16. Fig. 16 shows the output when Reflection is disabled.

Shadow

Use the Shadow check box to define whether or not shadows should be included in the render calculations. If you select the Limit Shadows to Soft check box, Cinema 4D will render soft shadows that render fast. Note that the rendering area or hard shadows is much more computationally intensive than the soft shadows. The soft shadows appear more realistic than the hard shadows. Compare Figs. 13 and 17. Fig. 17 shows the output when Shadow is disabled.

Limit Reflections to Floor/Sky

Use this check box to cause the raytracer to calculate the reflection of the floor and sky onto the reflective surfaces in the scene and not onto other objects. This option when selected takes less time to render. Therefore, you can use it in test rendering or when you have to meet a deadline.

Blurriness

Use the Blurriness check box to define whether or not the blur effect for the Roughness and Transparency material channels [blurriness resulting due to Roughness value] should be included in the render calculations.

Cache Shadow Maps

Cinema 4D calculates shadow map for each light in the scene that casts a soft shadow. A shadow map is used to define where shadows will be rendered. In a complex scene, the render time go up considerably if shadow maps are rendered. When the Cache Shadow Maps check box is selected, the shadow map will be saved when you first time render the scene. The shadow map will be saved in the scene's Illum folder with the name **.c4d.smap. This folder will be created automatically, if there is not one already.

Active Object Only

When this check box is selected, only the selected objects will be included in the render calculations.

Default Light

If you do not have a defined light source in the scene, a default light is used to render the scene. As soon as a light source is added, Cinema 4D automatically disables the default light.

Caution: Default light

When you use a Sky object with the HDR texture, the auto light is not disabled. If you add GI to scene, the auto light will be disabled when you render.

Textures

Use the Textures check box to define whether or not enable or disable textures when you render. You can disable this check box for a test render or when you are using the Cel renderer. When this check box is not selected, bitmaps will be replaced with the black color. When a texture is missing during rendering, Cinema 4D displays a dialog box. If the Show Texture Errors check box is selected and you confirm the alert, the rendering will continue without the missing texture. If you select this check box, rendering will be cancelled after you confirm the alert.

Volumetric Lighting

If this check box is selected, shadows will be cast in the visible light. This option is render intensive therefore you can disable this check box for test render.

Use Display Tag LOD

If this check box is selected, the renderer will use the level of detail specified in Display tags.

Render HUD

Select this check box, if you want to include HUD in the rendered image or image sequence. The left image in Fig. 18 show the HUD elements in the editor view whereas the right image in Fig. 18 shows the elements in the render view.

Render Doodle

Use this check box to define whether or not the Doodle function should be included in the rendered output.

Sub Polygon Displacement

This option is only available with the Visualize and Studio modules of Cinema 4D. You can use this check box to globally deactivate the sub-polygon displacement without having to do it separately for each sub-polygon displacement material. You can disable this check box for test renders.

Post Effects

Use this check box to enable or disable post effects globally.

Identical Noise Distribution

If you use low settings with many of the Cinema 4D effects, they produce grainy results. These results are often referred to as "Noise". Some of these effects are given next:

Area shadows

Subsurface Scattering (in the Direct mode)

Depth-of-field

Motion blur

General sampling in the Physical renderer

Post effects like Global Illumination, Ambient Occlusion, etc

If you select the Identical Noise Distribution check box, the noise distribution [even if no parameters are animated] will be random for each rendered frame which means that each successive frame will have random noise distribution.

Caution: Noise distribution

Disable this option for animations as it will produce unexpected results. However, if you want to produce stills that look identical to each other as much as possible, select this check box.

Caution: Noise distribution

The settings such as multi-threading can still produce randomness. This can be seen