Creating an Architectural Illustration Using Reference Photography

Note from the editor

This post was written by Pete Maric.

Pete designed Go Media's beautiful studio in Cleveland, Ohio. What else do you want to know? Well, he's also worked with three of the top 50 retail design firms in the United States. He has had the pleasure of working for brands such as Adidas, Nintendo, Everlast, and Dick's Sporting Goods, among others. His work has been featured in local, national, and international publications including The Adobe Illustrator CS3 and CS5 WOW books, Photoshop User Magazine, Cleveland Magazine, House Trends, and Architecture in Perspective. He also teaches 3D modeling and animation at Tri-C Community College and plays guitar.

Let's get started!

As always, it's a pleasure working with Go Media! I was excited to create his illustration for their headquarters exterior renovations, and my main goal was to make it look as good as possible.

In this tutorial I'll walk you through the process for manipulating photographs, compositing 3D elements using Cinema 4D, establishing perspective grids, and using elements of the existing photo to create an accurate illustration.

Step 1: Fix the Photograph

Drag guides next to the building walls, double click the background layer. Edit > Transform > Skew. Drag the corners of the image using the skew function until the walls are lined up with the vertical guides. Flatten image. Use the crop tool to resize the canvas, dragging the handles past the edge of the image to the desired aspect ration/composition. Save image.

Step 2: Create 3D Elements

In Cinema 4D, create a new material and import the corrected photo inside the color channel, uncheck 'specular'. Create a background object and place the new material on the background. Now the photo should be visible in the perspective viewport. If the photo looks disproportionate, too long or too narrow, you'll have to match up the output size of your file with the aspect ratio of the photograph. To do this, open the render settings and background material so you have both windows open next to one another. In the material editor, color tab, the resolution size is right under the imported photo. Type these numbers into the render settings output width and height.

Step 3: Create the Bike Racks

To create the Go Go Go bike rack, start with a spline text object and type in the letter 'G' using Frutinger font. In the front view trace the center of the 'G' with a Bezier spline. Next create a profile with a circle spline, then drop the Bezier and profile splines into a sweep nurbs object. Change the 'G' text spine to an 'O' and repeat the same process. Group the 'G' and 'O' into a null object, then duplicate using a Mograph cloner to create three 'Go' bike racks.

Step 4: Compositing

To composite the bike rack into background, add a floor plane and use the grid in Cinema 4D as a guide to match the floor plane and 'Go Go Go' bike rack to the perspective of the photo.  Add the background material onto the floor plane and use a frontal projection. Right click on the floor plane > Cinema 4D tags > Compositing Tag. Inside the compositing tag, check 'Compositing Background' so the floor plane is not visible in the final render. Add a camera, right click the camera > Cinema 4D Tags > Protection Tag.

Step 5: Light the 3D scene.

Create two omni lights; one for the main light source with hard shadows turned on and the second as a fill light without shadows, and position them into place. Use the photograph to determine where the light source is coming from, this is where the main light source should be placed (top right of photo). In Photoshop, pick the color of the light (sky) using the eyedropper tool and enter the RGB values for both of the omni lights colors in Cinema 4D. Additionally, use a sky object with an HDRI material for reflections on the bike rack.

Step 6: Render the Cinema 4D Scene

Open the render settings, make sure the output size matches the resolution of the photo. Click effects to add a Cel Renderer effect. Check 'Outline' with edge color set to black and background color set to white. Specify a save path and render the line drawing.

Next, create a multi-pass render. In the render settings, check 'multi-pass', then 'add image layers' with the multi-pass button. Turn on Global Illumination and Ambient Occlusion via the effects tab. Check Save > Multi-Pass Image > Check 'Multi-layer File' > specify a save path, name your file > hit render.

Step 7: Establish the Perspective Grid

Since the perspectives in photographs are usually not 100% accurate, it is important to establish a perspective grid to work off of prior to creating the final line drawing.

In Photoshop, create two new layers; one layer filled with white and opacity set to 50% and a new layer for a rough perspective grid. On the perspective grid layer, choose a red color and start laying out the perspective grid using the line tool. First establish the horizon line which should be at approximately 5'-6" above the ground (5'-6" is the average person's eye level). If there are not any people in the photograph, you can use other elements to approximate this height such as doors (6'-8" average height) to get as close as possible to 5'-6".

The next step is to find the vanishing points, where the perspective lines converge. In this illustration, based on a 2-point perspective, one vanishing point would be on the left side (as shown in the illustration below) and other point on the right, way off of the canvas and not visible in this illustration.

Once the horizon line and vanishing points are established, draw in some general perspective lines for important architectural elements such as building lines and top and bottom of windows. Continue to block in the new elements like signage and awning.

Step 8: Create a Final Line Drawing

Open the cel render created in Cinema 4D > Select All (Command A) > Copy (Command C) > Paste (Command V) into the illustration file. To create the rest of the line drawing, use 4 different line weights all on separate layers; 3pt, 2pt, 1pt, and an additional 1pt w/ 50% opacity. Start by drawing with the heaviest line (3pt) on the bottom of the building and bottom of sidewalk. The 2 pt line can be used for the building outline, 1pt line for interior details like windows and doors, and thin line for corbels/crown, garage door, and background trees.

When creating the line drawing, we can take a little bit of creative liberty from the existing site conditions. For instance, in the existing photograph, the telephone pole by the corner of the building is slanted and blocking the new awning. Let's straighten this so it's completely vertical and move it over to the right a few inches so it does not block the new awning. Additionally, we can slim down the foreground telephone pole and move the street names down so they are visible in the illustration.

Remember, we are trying to create an idealized representation of this building. If a few elements need to be shifted around for the sake of clarity, feel free to exercise your creative license. Just make sure to run these changes by your client and get their approval prior to proceeding to the final rendering.

Step 9: Establish a Color Scheme

Use the eyedropper tool in Photoshop to select a brick color from the existing photograph. Launch the website www.kuler.adobe.com, input the brick color's RGB values to create a custom scheme, then play around until you come up with a good-looking color palette.

For this illustration, I started with the color of the existing brick, played around with Adobe Kuler, then experimented with different sky gradients in Photoshop until I came up with a scheme that worked for this building.

Step 11: Set Selections

Before adding color to the illustration, set selections for important architectural elements. Use the pen tool to draw a path around the building > Command + click the path in the path palette to activate the selection >  Select > Save Selection > name the selection 'building' > Hit OK. This will create a new channel in the channel's palette. Repeat this process for the windows, go bike rack, and foreground telephone pole.

Step 12: Render the Illustration

Start the rendering by creating a custom gradient using the blue color from the color scheme with a yellowy/orange color. Create a new layer, set it to multiply blend mode, and drag the gradient from top to bottom to create the basic color for the sky. When rendering, starting with the sky color is a good idea because this sets the mood for the entire illustration. Next, add a layer mask to the gradient > command/click the 'building' selection in the channels palette > paint away the building, but let some of the color on top and bottom bleed into the building.

Next, create additional layers for the sidewalk and street, set blending mode to multiply, pick colors from the existing photo, paint in street and sidewalk.

Step 13: Render the Windows

Window Color: Duplicate the sky gradient layer > Layer > Layer Mask > Delete, and rename the layer to 'windows'. Create a new layer mask in the layers palette > Command/Click the windows selection in the channels palette > Select > Inverse > use a large brush and paint away everything, leaving just the color for the windows. Duplicate the windows layer and reduce the opacity to around 50%.

Window Reflections: Open a photograph of a cityscape to be used for the window reflections > Select all (Command A) > Copy (Command V). Jump over to the illustration file > Command/Click the 'windows' channel > Edit > Paste Special > Paste Into. This will paste the photo into the window selection. Click the window layer > Edit > Transform > Skew > manipulate the pasted photo until it somewhat matches the perspective of the illustration. Add a 4pt gaussion blur to the photo and reduce the opacity to around 40%.

Window Light Rays: Create a new layer > use the pen tool to draw some light rays > fill with an off white/yellow color > add a layer mask > mask out all areas leaving the light rays only in the windows.

Step 14: Render the Brick

For the building, we'll use as much of the existing photograph as possible. Duplicate the background photograph > add a watercolor filter (Filter > Artistic > Watercolor) > and drag the layer to the top of the layer stack. Add a layer mask > activate the building selection > Inverse the selection > paint away everything except the brick. Activate the window selection > mask out the window area to reveal the rendered windows from the previous step.

Step 15: Create a Brick Pattern

On the duplicated background layer, select a portion of brick using the Polygonal Lasso Tool. Create a new file at 11x17 inches, drag the brick selection in to the new file. Use the skew transform tool and align the top and bottom so they are horizontal, not slanted. Duplicate this layer to create a consistent brick pattern.

Next, create a new layer and draw grout lines using the line tool in Photoshop.

Step 16: Fix the Inconsistent Brick Pattern

Flatten the new brick and grout pattern > Select All (Command A) > Copy (Command C) > jump over to the illustration document and paste the brick for the front of the building. Use Edit > Transform > Skew to match the new brick pattern to the perspective of the illustration > mask away the areas for the windows, doors, telephone pole, and signage. Repeat this process for the corner of the building and left side.

Find a brick pattern on www.cgtextures.com and use this texture to render the building on the far right side.

Step 17: Add Background Trees

Duplicate the original brick layer (the one with the watercolor filter applied) > Mask out everything except the background trees, cars, and grass > set the layer to 'Multiply' blend mode > Reduce opacity to 90%. Fix any blotchy grass areas with the clone stamp tool. Duplicate this layer > flip horizontal > move to right side of illustration > mask out unwanted areas to create the right side tree.

Tip: Keeping all of the elements of the illustration on separate layers will give you complete control over the final look of the finished piece.

Step 18: Render the Go Bike Rack

Open the multi-pass file that was rendered from Cinema 4D. Double click the 'diffuse' layer > drag all layers into a group > name the group 'Go Bike Rack Render' > drag the entire group into the illustration file. Mask out each multi-pass layer individually and place the group into position.

Step 19: Render the Telephone Poles & Signage

For the telephone poles, use the background photo with a watercolor filter applied, mask out each telephone pole individually and keep all poles on separate layers. For the 'Lorain' & 'W.45 St' signs, use the text tool in Photoshop and skew each word into position.

For the 'Go Media' main sign, use the original reference image and cut/paste the sign into the illustration. Use Edit > Transform > Skew to match the perspective of the illustration.

To create the front awning, add a new layer, set it's blending mode to multiply and paint in the black part of the awning. Copy/paste the Go Media logo mark from Adobe Illustrator into Photoshop. Use Edit > Transform > Skew to match the perspective of the illustration. Create the address in Photoshop using the text tool.

Step 20: Add People and Cars to Populate the Illustration

Turn on the perspective grid that was drawn prior to creating the final line drawing. Open your people and cars stock files > add watercolor filter to each file > place into illustration. Tip: Make sure that the eyes of every person are lined up with the horizon line.

For this illustration, stock files were used from www.realworldimagery.com and www.doschdesign.com.

Step 21: Add Shadows

Turn off all layers except the final line drawing and entourage (people & car). Create a new layer and manually paint in the shadows using a hard brush and a cool grey color. Set the shadow layers blend mode to multiply. In this illustration, the light source would be coming from the upper right.

Step 22: Final Touches

Street Reflections: Duplicate the original photograph > flip vertical > move down so the building is reflected in the street > add a gaussian blur > mask out everything except the building > reduce the opacity to 18%.

Birds: Use a custom brush > turn on scattering in the brush palette > choose a blue color from the sky > turn layer to multiply > paint in a group of birds.

Highlights: Create a new layer > use the line tool with a 1pt line > paint highlights on the right side of all architectural geometry.

Light Bursts: Create a new layer > set blending mode to overlay > pick a yellow color > paint with a soft brush over the front of the building > reduce the opacity to 60%. Create a new layer set to overlay and paint with an orange color on both right and left sides of the illustration.

Border: Fill a new layer with a dark blue color set to multiply blend mode > mask out the center of the layer.

Texture: Drop a watercolor paper texture on top of the entire illustration and turn the blend mode to multiply.

Step 23: Revisions

One thing that you should always anticipate when doing illustration work are client requested revisions. This is a very important thing to keep in mind when setting up your working files. Although assigning each line weight and all aspects of the rendering to it's own separate layer may be a little bit more time-consuming up front, it pays off when you have to go back and revise your files. Tips: Keep everything on a separate layer, organize your layers into groups, and name all layers.

A few of the revisions to this illustration were to replace the side brick with a painted grey color, change Go bike rack to a brushed metal finish, and add clouds and a hot spot in the sky behind the building.

Change brick to grey: First turn off the new brick pattern in Photoshop to reveal the existing grey brick color. Next, use the clone stamp tool to touch up any wires, unwanted poles, and grass/weeds growing on the bottom of the building.

Change bike rack to a brushed metal finish: Open the Cinema 4D file and replace the Go bike rack yellow material with a stainless steel found in the content browser. Re-render the multi-pass file and replace the existing yellow color in the illustration with the new stainless steel.

Step 24: The final illustration!

Pour yourself a coffee warmer, you're done!