Photoshop image manipulation

I’ve had the opportunity recently to put my Photoshop skills to use on a few small projects. Here are two before and after images, one showing adjustments to an interior marketing photograph, and the other showing a simple brick proposed addition.

interior photo with strong highlights on ceiling and floor
interior photo with ceiling highlights reduced, and floor adjusted to reduce glare

And here is the exterior image, showing the simple brick expansion and matching roofline.

existing condition
image showing the proposed addition


Material ID channel tutorial

Having the material ID channel has been an immense help in compositing images in post-process. This is a tool that allows you to mask out a material and replace it with a suitable texture. I thought I would share my steps in making this image using the material ID and Alpha channel.

Step 1. select material ID color. In the material editor, select the material you want to mask, and pick a color other than black. Also, use a color for the diffuse layer that is low saturation, this will be important later.

Step 2. Select the material ID channel in your VFB dialogue. I also have the alpha channel selected since I am putting my own sky behind the image as well.

Step 3. When you render your image, save the image as a “.png”, and you will have three files. Your rgb color map, an alpha map (which is also the transparency in your first png), and a material_id map. (color and material ID shown below:)

Step 4. Open the color and material ID images into your image editor (one that can manipulate and overlap layers or levels) I am using Photoshop, so the rest of this is referencing PS.

Step 5. Select the texture to use as your background and open that in PS as well

Step 6. Arrange the three images so that material ID is on top, then color image is next, and the background is at the bottom of the stack. Make a copy of your color image.

Step 7. Make a selection your material ID color on the first layer by using the “magic wand” tool in PS, set to a tolerance of 5. Then choose the color layer in your layer window and run the following command: Layer -> Layer Mask -> Hide selection.

(If you turn off the copied color layer and material id layer, you will see this:)

Step 8. Make a selection of the black color on the material ID layer. Choose the copy of the color layer in your layer window, then run the following command: Layer -> Layer Mask -> Reveal selection. Next turn off (or delete) your material ID layer. Change the transparency of the copied color layer to “multiply” – this will cover the background with the shadow pattern from the render. If you have a color that is low saturation, the shadows should look fine. If you have a strong saturation, you may need to reduce the saturation on this layer so the colors are more normal. Adjust transparency as needed (mine is at 74%)

Step 9. Create a new layer and airbrush in some shadows under the bushes.

Final Architectural Illustrations

I’ve finished a set of illustrations, both interior and exterior for the restaurant shown in the previous post. There were a few changes from the preliminary images: new lighting fixtures, revised furniture (pub height tables and bar stools to match the table seating,) and I’ve also added more detail and texture to the images. The set of images also include some exterior views, showing the entrance, the rooftop dining terrace, and outdoor patio. Click on the illustrations for a larger image.

Restaurant Interior Rendering

This week I’ve been working on a rendering for a new restaurant in DC. I have finished building the base model in sketchup, along with all the furnishings that go into giving the interior and exterior spaces a certain character. I’ve started now on the illustration portion of the project, where I take the model I’ve made and create a watercolor style rendering of selected views. Here is the first image I’ve drawn.