As promised, I put together a video tutorial explaining the workflow that I use to create colored interior elevations using only Photoshop. There was a lot to go over, and I'm surprised I was able to fit it all in one 15 minute video. The steps are not difficult in terms of skill required, however, the sequence of steps to build up the elevation plays a big role in the success of the final image as well as maintaining control of all of the layers. The video is broken down into 6 steps which are summarized below.
STEP 1: POCHE
In the video, I filled in the section cut and exterior of the illustration in Photoshop. This was done to simplify things, however, I would strongly suggest executing this step in CAD or Illustrator for more precise final results.
STEP 2: TEXTURES
In this step, the textures of the walls and other architectural elements are added. One things I suggest doing is merging all of the same textures into one layer (such as merging all of the wood textures in the different rooms into one layer). Many times, I want to adjust the hue, brightness, or levels of certain textures. Minimizing the amount of layers means I can make these changes quickly.
STEP 3: BACKGROUND
This step involves adding background information that can be seen through windows. It's very easy for the background to get distracting, pulling the viewers' attention away from the interior spaces. To avoid this, I tend to make the backgrounds more monochromatic, meaning I stick with one hue of color. In this case, I chose blue to compliment the warm tones of the wood.
STEP 4: SHADOWS
This step is an important part of the process, and is where depth is given to the elevations. My advice is to go one room at a time like in the video. Shadow is added where you have a corner condition such as where the wall meets the ceiling or where a wall meets another wall. Also when there is a change in depth, shadow should be added such as in the stair railing. Check out my "Ambient Occlusion" tutorial or my "Quick Sections" tutorial which both cover the topic of adding shadow in more depth.
STEP 5: LIGHT
Step 5 discusses adding spot lighting and accent lighting. This puts warmth into the illustrations and brings attention to the important parts of the space. Adding light is as simple as adding white paint and setting the layer blend mode to "overlay". To punch up the strength of the light, duplicate the layer.
STEP 6: POPULATE
The final step invloves adding scaled people and furniture. This is where a lot of my time is usually spent. I have a huge library of people already cut out, but finding furniture at the correct angle can be difficult. Most of the time, this means distorting pics to look like they are in elevation. Take your time at this stage, because this is where a lot of interior elevations can get ruined with shotty Photoshop work.