There are a few ways to bring work from DAZ Studio 4 into Photoshop. This article gives an overview of the possible methods. For more detailed information, see the respective documentation for DAZ Studio 4 or DAZ 3D Bridge.
If you simply need help installing and setting up 3D Bridge, see this article:
3D Bridge
https://helpdaz.zendesk.com/entries/21045731-how-to-install-and-use-3d-bridge-in-daz-studio-4-pro
Bridge
This feature requires the installation of the 3D Bridge plugin which is sold separately with your purchase of DAZ Studio 4 Pro. DAZ 3D Bridge in Studio 4 only works with CS5 and above. If you have CS4 or earlier, it will not work.
Make sure you have installed and activated the DAZ 3D Bridge plugin first. To do this, go to HELP --> About Installed Plugins. Look for the Bridge plugin and make sure it has been activated. To use Bridge, have both DAZ Studio 4 and CS5 running. In Studio, go to FILE --> Initialize Photoshop 3D Bridge. In turn, in Photoshop, you have to go to Automate
.u3d Format
You can export files in your scene from DAZ Studio 4 in the .u3d format that can be used in CS5. Be aware that this is a 3D format. In DAZ Studio, select the model you want to export. Then go to FILE --> Export. Choose the .u3d format (Universal 3D) and then save the file to the hard drive. In Photoshop, you'll need to browse to the file location to find and open it.
Render Format
This is the easiest way and available in all editions of DAZ Studio 4. In Studio, simply render a scene and save the render as a picture file. In Photoshop, you can then go to FILE --> Automate --> DAZ Studio 3D Bridge.
Bringing Photoshop Files into Studio
It's important to be aware that Studio is primarily a 3D application and that Photoshop is primarily a 2D application. You can bring 2D pictures from Photoshop into DAZ Studio. To do this, save the picture in Photoshop in a format that can be used in Studio, such as .jpg, .png, or .psd. The Photoshop Document format can be used in MLIE (Multi-Layered Image Editor). Otherwise, the .jpg and .png formats are standard. There are two ways to use 2D files in Studio. You can use a 2D file, such as a .jpg file, as a backdrop. You can apply a 2D file to the surface of a model.
To create a backdrop in DAZ Studio 4, go to EDIT --> Backdrop. In the new window, browse to and select the 2D file that you wish to use.
To apply a 2D image to a surface, select the model in the Scene Tab. Then go to the Surface Tab and select the surface or surfaces which you wish to apply the image to. Then choose the property on the right half of the tab, such as 'Diffuse Color' that you wish to use the image for. You'll need to click the 'browse' button. Then browse to and select the image on your hard drive.