UV Editing with MicroStation, Blender and Photoshop

Introduction

MicroStation has a fantastic material system. With the material editor you can materialize a model in a very short amount of time. When we have to materialize an object with a bigger precision however, it can be a real challenge. A possibility in this kind of situations is to work together with an other application.

 In this wiki I will try to explain the way I work when i have to bend a material around a curved mesh surface. Of course there are many other situations where you can use this method for. I use this for example also for adding photo's of existing houses to objects. With this way you can materialize an existing town or residential on a very fast and precise way. 

The programs I used where:
-MicroStation v8i SelectSeries 3 (08.11.09.209);
-Blender 2.61 (r42846), you can download this open source application on www.blender.org or graphicall.org;
-Photoshop CS 5.

A little knowledge of Photoshop is required to follow this tutorial.

If you have a question or comment, please feel free to post a comment.

Tutorial: 

1) Select the element you want to materialize, hold down the right mouse button, and select isolate.

2) Go to File - Export - and choose OBJ. In the little window that appears check the invert Y and Z option. then choose export. Choose a location and filename and press Save. 

3) Open Blender, select the cube (with the right mouse button) and press delete.

4) Choose File - Import and choose OBJ. Select the file you exported from MicroStation. 

5) Zoom out (Scroll) until you see the object. Go to the button with the two squares above each other and the rectangle next to it. Choose UV Editing.

6) Press numpad 5 (view persp/ ortho) and numpad 7 (top view) In the right screen select the object (right mouse button) and press tab (or press the button you see in the image). Now you are in editing mode. Press A to select all the verticals. In the Vertical button area scroll down until you see the UV mapping section. 

7) Choose Unwrap and Project From View.    

8) Select all (A) and rotate the object until it's about 90 degrees compared to the screen (R). Move the object in the  middle of the window (G). Scale the object until it fit's in the window (S). 

9) Press the UVs button at the bottom and choose export Export UV Layout. I chose to export it to an EPS file.   

10) Open PhotoShop and open the EPS file. You should see something like the image below.

11) Open the image you want to bend along you're object. I chose a seamless image of a road. 

12) Press ctrl-t (Free Transform) and fit the concrete to the uv (see image below).

13) Copy and past the images of the road above each other.

14) Copy the layer and press ctrl-t. Go to warp modes and set warp on Arc (see image). Drag the little square in the middle to the left until it fits in the curved part. 

15) Repeat  step 13 and rotate it 90 degrees. Position it next to the curved road. You should see something like the image below. Go to File and Save the image as a tif, png or jpg image. 

16) Go back to Blender, go to the UV window, choose Image and open the image you saved in Photoshop.

17) Select the vertexes which are not aligned with the uv (press C and you can brush the Vertexes you want to select). With G you can position the vertexes to the correct place (see image).    

18) Go to Default layout (see step 5) and set viewport shading to textured (the button with the Sphere below) you could see and test the result. Go to File - Export and Choose .obj or .fbx (fbx is in the version I use more stable).

19) In MicroStation open the .obj or .fbx file and save it as dgn. 

Now you can use the object like you want. You can use it for example as a reference and merge it to the original model. 

Have fun!