I am having a couple of problems using object subtraction. I am trying to "drill" a hole through a rectangular (box) shape with a cylinder. When I make the subtraction I end up with a lot of excess lines/edges as shown here:



This messes up the texture that I try to apply, so I trimmed all but one of the edges on each side. When I try to trim the last one I get the error "The selected edge is not shared with another face. Try selecting each point individually". Here is the shape at this point:



On top of this, when I try to drill another hole the first hole closes up. Here is the solid and wireframe view of the box at that point:



Anyone have any suggestions on how to remedy these problems?

I noticed this too.

You must keep some edges from the first hole.


Then


Boolean operations are somewhat tricky to use.
I discussed a little of boolean operations with Richard.
2 sides effect, I don't like after a boolean operation : some edges are added, colinear edges are removed (I want to keep then for texturing) and texture is removed.

I wish boolean operations would keep the object as it is (except for the result of the operation... of course) with its texture.

I don't use the boolean ops to create this kind of object....you're not in control of all the points and edges....I sort of work from the hole outwards.
See attached pic.....
1) Start with a cylinder, it's longtitude must be divisible by 4. Select the two end caps and run the Insert operation.
2) With the two inserts selected run the Bridge operation.
3) The cylinder after the Bridge operation.
4) Select the outer faces and scale equally in x and z
5) Select 4 of the faces in line with the x axis and run the Equalize operation on the x axis.
6) Repeat for the rest of the faces changing the Equalize op setting to z as required.
When your done scale along the y axis as required.

This takes longer to write than to do....takes about 2 mins.

Just select the faces creating the hole and drag in x and z to re-position the hole.

Bazza

This message has been edited. Last edited by: Bazza,

Hole.jpg (42 Kb, 45 downloads)

By merging two of these together...welding the seam and deleting any internal faces you can create all sorts of shapes with the holes scaled and positioned as required.
Just got to watch the face count and not get to carried away with it.
If you can get away with the basic cylider only having 12 longtitude divisions this will help.

This one has 16 and took around 10 mins to construct....120 faces

Bazza

Holes.jpg (75 Kb, 30 downloads)

Interesting method of creating holes.

However, it is may not be possible to use it when you want to make holes in complex shape (train body, for example) and when you need to adjust holes at specific positions.

Each time I used boolean operations, I needed to rework the model because of unwanted / unnecessary points and edges or because of removed points / edges that I needed.

An example of union

After union of the joint around the window:


after cleaning the object:

Interesting way to create a hole. I'll give it a try. My biggest problem with the boolean operation was I need to create a rectangle with 10 holes (for a 3D image of a cribbage board) and each operation screwed up the work from the previous one. I hope this is cleaned up in future versions.

quote:

for a 3D image of a cribbage board

Can't you just use a texture,an image of an actual cribbage board....do you really need the holes in the geometry of the object.

Bazza

It's ages since I played crib but this is how I would build a crib board...see the attached pic.
No holes in the geometry just uses 4 textures.
Took about 90 mins...the textures could still be improved.

Bazza

CribBoard.jpg (74 Kb, 39 downloads)

I would also avoid boolean - if you do need to use them then try splitting your original face up into small faces so there is only one hole cut per face ?

Booleans are useful, of course, but should be used in moderation.