Tutorial : Modeling with Blender for precision work

Here’re some interesting advices and ressources to work with Blender as a precision tool.

That is, when you want to model anything with precision or accuracy to an existing object. Why bother with this ? Because I’ve learned to value the acuraccy of a car model as well as the simple beauty of a render. It’s a matter of taste, and I just think it’s more grateful to achieve an accurate model than to rush to produce something-looking-a-bit-like-but-not-really-the-same.

By the way, happy new year !

If you don’t want to read much

For precision modeling, the shortest advice is : define yourself the scale you’ll be using for your model. By writing this, I mean that there is no feature in Blender such as “define which size is a meter or a foot or a parsec or whatever length unit you can think of”. There is only Blender units.

So the first thing to do is, define what a Blender unit represents. For example, I’ve always used “1 Blender unit stands for 1 meter”. So any precision like, e.g., a 5 mm gap between 2 body parts on a car is reachable : it’s just, for that example, a matter of 0.005 Blender unit.

Still there ? Want to read (much) more ?

For a longer advice, one top level reading is the book from Robert Burke. He was published in BlenderArt some issues ago, and the book is a longer version of the published tutorial. There was an article on Blendernation about it some days ago : Precision Modelling PDF Guide at BlenderNation. The guide is available on his site : rab3D.

This is a 150 pages book. It’s really worth reading !

Bonus : another way to use blueprints

There is another scale or resolution to use with Blender.Maybe you’ve also heard of the “native resolution of Blender”.

As far as I know, it’s used only for background texture. It define which size will have a picture (of a given height and width in pixels) within the Blender viewport.

The so-called native resolution of Blender is 512 pixels for 2 Blender units. The screenshot below shows a 512×256 blank image loaded in Blender, with a zoom factor of 1.0 :

Blueprint size

To show up such a picture in background, use the menu entry “View > Background image” with any 3D view. I’ve added a 2.0 Blender units edge to explicit the dimension, below the picture.

If you want to use a given scale like I wrote above, you then have to compute the zoom factor to use : if this picture was a print of a car 4.73 meters long, you just put 4.73/2 = 2.365 a zoom factor.

The last control to use within that panel is the offset : you can move the picture to match any arbitrary reference. Use the “Xoffset” and “Yoffset” controls to specify how much the picture should be slided respectively horizontally and vertically. The figures you specify there are in Blender units, so for the scale I use, in meters.

This is an alternate way to setup blueprints to the tutorial I’ve wrote some times ago : Blueprint setup in Blender.

I still keep working the way I described in that tutorial, because it has two advantages I think :

  • No need to use a viewport subdivided in four 3D views to show 4 different pictures, like the front / rear / front / top views of an usual blueprint.
  • It’s easier to show / hide blueprints : instead of clicking the “Use” button you can see in the above screenshot, I dedicate a layer for blueprints and with keyboard shortcuts like Shift+5KEY (if the UV-mapped blueprint box lies in the 5th layer)

Of course, my previous way has a drawback : you have to show the parts as wire. Otherwise they’re will be hidden on the UV-mapped blueprint box.

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