is it possible to enter absolute dimensions in a numerical form for a selected object or mesh?
The problem is: I want to use Blender as a kind
of CAD-programm in order to create a pipe for example. The pipe should be 10 mm in diameter with a wall-thickness of 1mm and a total length of 1 m.
What I have tried is the following:
created cylinder.001
numerically translated cylinder.001 to
x-size 1
y-size 0.01
z-size 0.01
created cylinder.002
numerically translated cylinder.002 to
x-size 1.1
y-size 0.009
z-size 0.009
applied boolean operation “difference” in order to create a pipe
The result does not look like the described pipe in any way.
Booleans are generally messy.
As for your pipe, I tried the things you described and got a relatively good result. Very tiny pipes, from your settings, though. Perhaps you could try scaling them up so you could see them better. How about 10, 1, 1 for x, y, z? Lots of extra verts from the boolean, though and tris. You could try cleaning them up with remove doubles, tris to quads etc.
The problem is not creating good looking pipes, but the creation of exact scaled parts.
E.g.: How to create a tube of dimension 1000x10x1 mm and an M8 screw attached to it?
Scaling a tube to a relatively good result does not help if it comes to construct a real bicycle from its 3d-object.
It would help alot, if I could enter real world dimensions from a real screw or a real tube. Using real dimensions is important, as I have to construct items out of parts that I can buy from my local hardware-store.
What I’m missing in Blender:
In Lightwave-Modeler, one is able to enter real world dimensions (m, mm, um) when creating objects. Its also possible to scale objects to an absoloute dimension in any axis in LW.
When it comes to use a rendering software for constructIon of real world parts, it is not sufficient to scale objects just by eye.
Blender’s target is as an art program, not a CAD program, so numerical adjustments and the like are not as easy as some arty features.
That said:
Blender has no intrinsic “length” for its units. In CG you can have a scene 1m wide or an identical scene 10m wide, and it would render the same.
However you can just say “1 blender unit is 1 metre” or whatever is appropriate, and just stay consistent throught the scene.
There are tools, such as “Edge length”, “Face area” and “Edge angles” which draw the appropriate numbers on the scene, and things like the NKey popup and numeric grab/rotate/scale modes for when you need accuracy.
To model your pipe, I’d do this:
Add a mesh circle. Circles, spheres and the like come into existance with a vertex at (1,1,0) for some reason that no doubt makes sense to someone, so its radius is 1.414 - so immediately I’d press S, 0.707, Enter to scale it down to radius 1.
I’d probably call 1BLU = 0.1m seems like a good scale, so for 10mm I’d scale it down by another 0.1 (hold Ctrl for accuracy).
Then E to extrude, S to scale and scale to 0.9 to get the 1mm thickness.
Select the lot and extrude up 10 units.
Bingo, to-scale 1000x10x1 pipe.
For the nut, I’d add a circle with 6 points to get a hexagon, extrude, cancel and Alt+M to merge the points in the middle. Then I’d turn on “Edge Lengths” and scale it to the appropriate radius, whatever it happened to be, and extrude it to the right width. I wouldn’t bother to make a hole in the middle since it’s going to be on the pipe anyway - modelling the hole would be a waste of time.
Yes, I found them already. I had hoped there was some really “tool” to actually SET the angle or length of an edge numerically. Also, the display of the angle disappears partially if I zoom in too much. But after all, it is a nice feature that can be helpful.
