McNeel Wiki

Site Tools

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Next revision 		Previous revision
Next revision Both sides next revision
rhino:booleanfaq [2020/08/14]
127.0.0.1 external edit 		rhino:booleanfaq [2023/11/19]
mitch_heynick [Boolean Frequently Asked Questions]
Line 12: Line 12:
 Everything you can do with Boolean operations you can also do manually by using the above four commands.  Using a Boolean operation only speeds things up by making it one procedure –- when it works... Everything you can do with Boolean operations you can also do manually by using the above four commands.  Using a Boolean operation only speeds things up by making it one procedure –- when it works...
  
-So, the first thing to keep in mind is that a **//solid//** understanding of how the component operations of Booleans work is necessary.  When all else fails, you can get the job done with these commands: **Intersect**, **Split**,  **Delete**, and **Join**.  Try undoing a successful Boolean operation and redoing it manually using those commands.  Get comfortable with the fact that this procedure will always get you where you want to go even if your Boolean attempts fail. +So, the first thing to keep in mind is that a **//solid//** understanding of how the component operations of Booleans work is necessary.  When all else fails, you can get the job done with these commands: **Intersect**, **Split**,  **Delete**, and **Join**.  Try undoing a successful Boolean operation and redoing it manually using those commands.  //**Get comfortable with the fact that this procedure will always get you where you want to go even if your Boolean attempts fail.**//  There are people who feel that using the manual Split/Trim/Delete/Join procedure and avoiding Boolean operations insofar as possible is a better way to model.  //The most important takeaway here is understand how this procedure - one of the basics of 3D modeling - works.//  If you do, you will not be stuck when some Boolean operation mysteriously fails later on - you will understand why and how to fix it.
 =====Boolean operation failed...===== =====Boolean operation failed...=====
 OK, why do Booleans fail?  First, it is the intersection operation that will determine the success or failure of a Boolean operation.  If a correct intersection is found, the rest is easy. But if Rhino has problems finding the intersection, the Boolean operation is guaranteed to fail.  So the key is to help Rhino find a good and complete intersection.  You can do this by setting up your model and file correctly, and also by understanding some of Rhino’s quirks and limitations. OK, why do Booleans fail?  First, it is the intersection operation that will determine the success or failure of a Boolean operation.  If a correct intersection is found, the rest is easy. But if Rhino has problems finding the intersection, the Boolean operation is guaranteed to fail.  So the key is to help Rhino find a good and complete intersection.  You can do this by setting up your model and file correctly, and also by understanding some of Rhino’s quirks and limitations.
Line 34: Line 33:
 **Coincident seams** – All objects have seams. Sometimes when the seams on two objects are at exactly the same place, Rhino has trouble with the intersection.  Solution: Either try to move the seam, or try moving one object just a tiny, tiny bit (if you can without making your model inaccurate).  Or try to do the operation manually. **Coincident seams** – All objects have seams. Sometimes when the seams on two objects are at exactly the same place, Rhino has trouble with the intersection.  Solution: Either try to move the seam, or try moving one object just a tiny, tiny bit (if you can without making your model inaccurate).  Or try to do the operation manually.
  
-**Coplanar faces</color** – If two faces of an object are on the same plane, Rhino may not be able to calculate the intersection. This is a fairly  common occurrence. Avoid building your model this way if you can.  Solution: As above, you may move the object slightly if possible. If not, you may have to do this operation manually.+**Coplanar faces** – If two faces of an object are on the same plane, Rhino may not be able to calculate the intersection. This is a fairly  common occurrence. Later versions of Rhino are much better at resolving these situations, but they may still occasionally fail. Solution: As above, you may move the object slightly if possible. If not, you may have to do this operation manually.
  
 **Nearly tangent surfaces** – Like the intersection of two equal diameter pipes at an angle.  The intersection often fails at the point where the surfaces are tangent.  Currently, there is no easy fix for this problem. **Nearly tangent surfaces** – Like the intersection of two equal diameter pipes at an angle.  The intersection often fails at the point where the surfaces are tangent.  Currently, there is no easy fix for this problem.
Line 40: Line 39:
 **Invalid objects** – If one of the objects you're trying to work with is invalid, Boolean operations will often fail.  Check for invalid objects by using the command **SelBadObjects**.  If one highlights, you need to fix it first before proceeding.  It is also recommended that you turn on automatic object checking. If invalid objects are created in the course of your work (or imported), Rhino will tell you immediately.  To do this, simply type **CheckNewObjects**.  This is a toggle, running the command again turns it off. **Invalid objects** – If one of the objects you're trying to work with is invalid, Boolean operations will often fail.  Check for invalid objects by using the command **SelBadObjects**.  If one highlights, you need to fix it first before proceeding.  It is also recommended that you turn on automatic object checking. If invalid objects are created in the course of your work (or imported), Rhino will tell you immediately.  To do this, simply type **CheckNewObjects**.  This is a toggle, running the command again turns it off.
  
-**Non-manifold polysurfaces** – Although Rhino doesn't currently flag these objects as bad, they can cause failure.  Rhino //shouldn't// create these types of structures, but under certain conditions it does, especially with V4.  The only way to find them currently is to check the properties of the object.+**Non-manifold polysurfaces** – Although Rhino doesn't currently flag these objects as bad, they can cause failure.  Rhino //shouldn't// create these types of structures, but under certain conditions it does.  The Properties/Details of an object will indicate if it is non-manifold, and you can use the edge analysis tool to highlight them.
  
 =====Manual construction and editing is sometimes needed===== =====Manual construction and editing is sometimes needed=====
rhino/booleanfaq.txt · Last modified: 2023/11/19 by mitch_heynick

Page Tools

© 1997-2024 McNeel • North America • Europe • Latin America • Asia • Korea     Recent Changes RSS Feed Driven by DokuWiki