Bitmapping a cylinder end

At times the need arises for a circular bitmap to be placed on the end of a cylindrical object and the process tends to give some Swifters a lot of grief. In much the same way as bitmaps are placed on square extrusions, the same is true for round extrusions. Most commonly the objects are dials, guages or watch/clock faces. This tutorial is mainly focused on correctly aligning the bitmap on the material. If you want to place a bitmap texture on the end of a cylinder, use this technique and place the extrusion as a cap on the end of the cylinder.

So how do we do it?



 Step 1 - The bitmap
 

When using the bitmap of your choice it actually does become a case of "size matters". The larger the image and higher the resolution - the better the finish when rendering. However if the image area is small within the render, there's no point using large files for, say, a tiny speed guage on a motorcycle.

The image on the left is 345x345 px in size and can be downloaded here.


 Step 2 - Creating the material
 

Go to - Setup > Materials. Highlight "Bitmap" from the list and select "Add Material...". Give your new bitmap texture a Name (e.g. 'watchface' ). In the Finish sub-panel, open the Ambient Color picker - select white. In the Color sub-panel, select "Bitmap Image" from the Pattern drop down menu. When prompted to select a file - select the watchface.bmp file. Leave all other settings at their default values! You can view the full panel image with all settings required Material Panel.

Hit "OK" and "Done" respectively.



 Step 3 - Creating the object
 
Creating the object is very simple. One of the improvements of Version 3 over Version 2 was the inclusion of a selection of preset shapes in the extrusion editor. By making use of the preset round extrusion it will speed up the process of creating our perfect circular object without the annoyance of all that hit and miss guess work to get the shape correct. Press the button in the extrusion editor for 'round extrusion' to create the cylinder.


 Step 4 - Applying and aligning the material
 
To understand the way bitmaps are placed onto the surface of extruded objects in Swift3D, I have created an illustration on the left of the extrusion editor environment to graphically help the explanation. The rear object represents the extrusion editor work area. As seen in the image, this is how the extrusion editor tiles the bitmap. Placing an extrusion's centre at 0,0 will make the bitmap seem to tile. You probably have discovered this already, rendering after placing a bitmap on an extrusion only to find the image ending up like a messed up jigsaw puzzle.


 
The front object represents the circle you just created in the extrusion editor. By remaining in the extrusion editor and moving the extrusion so it is placed over the bitmap in one of the four quadrants with its 2 edges touching the axis lines will produce a correctly aligned bitmap finish.


 

I chose to move the extrusion left and up as seen here, so now the extrusion has the bitmap correctly aligned to it.

Do not move the extruded object in the main editor to try and align the bitmap. It simply will not work that way. It has to be adjusted in the extrusion editor.


 Step 5 - Sizing to fit
 

Go back to the main editor.

"Hang on!" I hear you say as you have eagery hit the quick render button to see how successful you were - "I have nothing like a great finish!"

What you should have is the image shown here. This is because the bitmap image is too large for the object. To get it to fit the bitmap you must increase the size of the extrusion.


 
Shown here are the results of progressively increasing the size of the extrusion using the Sizing option from the Properties Menu. The largest extrusion was the result of increasing the size of the extrusion by two. It is just fortunate for me that for this particular project it was exactly the right increase in size to fit the bitmap! So when sizing up it is a stepped process of increasing size - checking the fit and repeating until the extrusion is large enough.


 Step 6 - Completing the scene
 
To complete the scene and put the bitmapped extrusion to work, I created the watch backing, the glass face, the winder, and the bottom connector in the lathe editor. Then they were scaled to fit. The silver knurls on the winder were a copy and paste of the winder and then its sweep angle reduced to 5%. I then copy/pasted it several times around the edge of the winder. The watch hands were created in the extrusion editor and sized to fit. The egg shaped sphere was a default sphere with its height reduced. The torus was also a default torus with its width widened a little. They were then scaled to fit.


 Step 7 - Final adjustments and rendering
 

The final adjustments applied to the image were a default chrome finish to all the silver parts. A default gloss black to the hands. A default glass finish to the glass face. A default gold finish to the winder. I then reduced the 2 default lights to a grey from the default white and shuffled them around until the lighting looked better from the camera angle I was using. I placed the default grey ripple gradient environment into the scene. To finish I placed another target light to illuminate the watch face.