Photoshop: Digital Renderings with Photoshop and AutoCAD Part I

Using AutoCAD and Photoshop together is a great way to produce high quality and easy to manipulate digital renderings and paint elevations. In part one of this two part series, I'll detail the process for getting AutoCAD drafting into Photoshop and applying simple textures to the drawing.

Stay tuned for part two which details simple Photoshop techniques to impove the depth and dimension in Photoshop digital renderings.

Photoshop: 3D Layers [CS3 Extended]

New in Photoshop CS3 Extended is the ability to import 3D objects in various formats (.u3d, .3ds, .obj, .kmz, and Collada file formats) as a Photoshop layer. While no substitute for true 3D rendering applications, this new feature adds a new dimension to collage rendering. For this example we'll be using this photo from everystockphoto.com and a 3ds model of a patio table.

To import the 3ds model, select Layer->3D Layers->New Layer from 3D File... and select the .3ds file to import.

After importing the 3ds file, Photoshop creates a new 3d layer of the object. Double-clicking on the layer icon in the layers palette reveals the 3D layer transformation tools which allow for positioning, rotation and sizing of the imported object.

Using the "Drag" and "Slide" tools to position the patio table in an appropriate perspective of the scene yields this finished image. (Press <enter> to accept the 3D transformation just like the Free Transform command.)

If the imported object includes any associated textures, these textures can be edited by double-clicking on them in the layers palette. New textures can't be created and existing texture mappings can't be modified, but the standard Layer Blending options will work with 3D layers (drop shadow, outer glow, satin, etc.). Additionally, modifying the structure of the model itself still requires the use of a bona-fide 3D editing application. (Why not give the open source alternative Blender a try!)

Photoshop: Replace Color

Earlier, we covered using 'Match Color...' to recolor a research image to represent a palette concept. A useful compliment to this tool is the 'Replace Color...' tool which we'll demonstrate here to recolor only a specific color in an image.

Here's the image we'll be working with:

In this image we're looking to replace the greenish color of the vessel with a more blue tone. After opening the image in Photoshop, we'll start the 'Replace Color...' command (Image->Adjustments->Replace Color...). The first thing you'll notice in this dialog is the selection preview in the middle of the dialog. This preview describes which portions of the image will be affected by the command -- white areas will be affected, while black areas will remain unchanged. By default, the eyedropper tool is selected in the upper corner of the dialog. Clicking on the green color in the image modifies the selection area to include only the green areas of the image. Using the eyedropper tool with the plus (+) icon lets us add colors to the selection set, while the eyedropper tool with the minus (-) icon will subtract colors from the selection set. The fuzziness slider controls the tolerance of the selection set to include colors similar to the selected colors.

Once we get the selection preview roughly selecting only the area we want to change (we're not going to be overly detailed here, as we're using this command as a visualization tool rather than for final output), we'll click on the target color swatch to pop-up the color picker. This color picker functions just like any other Photoshop color picker -- we can either choose a color directly, or if we want to match a color already in the image, clicking in the image functions just like the eyedropper tool.

Once we're satisfied with the replacement color we've chosen, we'll click OK to produce the final result.

Looking at this image, you can see that some colors were replaced in areas that we didn't particularly want to replace (top right corner). If we're looking to produce a final output, we may have to do some work with some other tools to create the precision we're looking for.

Photoshop: Quick and Dirty Depth of Field Effect

Creating a shallow depth of field effect is a feature included in almost every 3D modeling and rendering program, but the effect can add valuable processing time to the rendering process. 3D rendering programs are excellent at recreating accurate depth of field effects based on distance from the POV. When effect is more important than accuracy, a quick Photoshop session can duplicate a shallow depth of field.

In this example we'll be working with this image:

We're looking to create a depth of field effect with the straw and the front edge of the glass in the sharpest focus. After opening the image in Photoshop, I'll switch to 'Quick Mask' mode (type 'Q') and using a brush with a very soft edge, paint a mask over the areas that should be sharpest in the final image. Varying the opacity of the mask as I get further away from the focus plane will improve the final version of the effect.

Once I've painted the mask, I'll switch back to 'Standard Mode' (type 'Q') and execute the 'Lens Blur' command (Filter->Blur->Lens Blur...). Varying the 'Radius' value effects the amount of blur applied to the unmasked areas of the image.

Clicking OK to accept the filter's action produces the final result.