Intersect command not splitting face
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Damn, this is embarrassing.
I am really sorry for spamming you guys with questions over the past few days
But once again, Sketchup is trying to kill me (at least thats what it feels like) and I have no idea what could be causing the problem. So: I am attempting to split my model in half by intersecting a box shape into it and then deleting half of it. When I pull the box to the right position and intersect, sketchup builds the edges on the surface perfectly, but it won't actually split the surface. So after intersecting, I select the surface that is supposed to be split, but when I select it the whole thing is selected, not half.Here I have the box positioned to cut the model in half
And here you can see the line that sketchup created, but it still selects the whole thing, when I click it
I have checked, the intersection has been done correctly and there are no visible problems with the line going through the middle of the model.
Does anyone know what is causing this?
Again, sorry for spamming this forum, it just seems I can't place a single line on this project without running into a solid brick wall
Thanks in advance, Kevin
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It looks like you may be intersecting in the wrong context. Are you intersecting while in edit mode of the actual helicopter group or component?
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@box said:
It looks like you may be intersecting in the wrong context. Are you intersecting while in edit mode of the actual helicopter group or component?
Yes, I double clicked the heli's group for editing and then created the box inside the heli-group and intersected in edit mode. Is that wrong? Usually worked fine... I also tried creating the box outside the heli-group and then intersecting with the group.
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That sounds right but your image shows different faces overlapping, so something seems wrong. I haven't followed your other thread about this heli so it might be something in there that explains it.
The nose seems to have a gray face coming through the selected face. Are you certain you are in the right section. Also I assume you are working on a large enough scale that tiny edges and faces isn't the problem.
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@box said:
That sounds right but your image shows different faces overlapping, so something seems wrong. I haven't followed your other thread about this heli so it might be something in there that explains it.
The nose seems to have a gray face coming through the selected face. Are you certain you are in the right section. Also I assume you are working on a large enough scale that tiny edges and faces isn't the problem.
Well, the face on the nose cone is simply the "end cap" of the nose, I just hid the outlines of it. I have tried all the modes I could think of but they all don't work, so I guess thats not the problem either. If you want, you can take a look at the model and see for yourself. Is there maybe some kind of plugin for intersecting, I could try?
Here's the model
Huey_1.skp -
There are a few issues with your model but simplest thing is to copy just the skin and intersect that. The extra bits inside your cockpit cause some problems. There are a few dodgy lines floating around and bits missing so it tends to connect through when it's all together.
Lying in bed with a my very slow, usually just radio pc and a thumball mouse, so can't do much with your model but here is half to get you moving.
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@box said:
There are a few issues with your model but simplest thing is to copy just the skin and intersect that. The extra bits inside your cockpit cause some problems. There are a few dodgy lines floating around and bits missing so it tends to connect through when it's all together.
Lying in bed with a my very slow, usually just radio pc and a thumball mouse, so can't do much with your model but here is half to get you moving.That looks much better, what exactly did you do? Just remove all the garbage on the inside of the model?
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AH well I was going to post the model, but Box beat me to it. But lying in bed must be trick, cause that's where I am too!
I found faces were disappearing so I scaled the fuselage up a hundred times to do the split. I think I did as Box. I grouped the main fuselage and added the face. Made the intersect with context in there. It took a long time on my laptop. -
Opened group, clicked once on the skin, copy, closed group, paste(not in place). Drew rectangle, push pulled to middle etc, intersected, deleted excess.
If you look at the junk inside there are some stray lines and broken edges. When modelling something like that you need to keep things clean and it is often easier to make things as components and work on them to the side. That way you don't get loose geometry fouling things up.
Edit: Next time Peter, nudge me, no point both of us doing it.
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@box said:
Opened group, clicked once on the skin, copy, closed group, paste(not in place). Drew rectangle, push pulled to middle etc, intersected, deleted excess.
If you look at the junk inside there are some stray lines and broken edges. When modelling something like that you need to keep things clean and it is often easier to make things as components and work on them to the side. That way you don't get loose geometry fouling things up.
Edit: Next time Peter, nudge me, no point both of us doing it.
I just did my best trying to delete all the junk, but I doubt that I got it all and I have the suspicion there might be some "invisible" screw-ups on the left side of the nose. You might have noticed, the lower left window under the nose cannot be selected seperately, even though it seems to be allright. So basically, I am trying to get rid of the left side of the model and continue on working with only the right side.
So this time I scaled the model up by 100, like Peter mentioned, and it actually worked, I can now select both sides of the original face seperately. But hey, here we go again
Now I have a bunch of faces dissapearing after the intersection. Looks like this:
Oh, and before I forget, when I try to copy just the actual fuselage, no windows, like in the file you posted, it ends up looking like this:
At this point I'm wondering how it is, that I havn't put my fist through the screen yet.
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I was getting those holes (in the first image). But it didn't happen when I scaled up.
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All those lines are simply how you have the softening settings set, triple click so all the surface and lines are selected and adjust the softening settings, window/soften smooth.
The problem front left nose is one tiny line that hasn't intersected properly. Remove redraw it and the window becomes separate. There are many other bad lines but that is the one causing that problem.
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@box said:
All those lines are simply how you have the softening settings set, triple click so all the surface and lines are selected and adjust the softening settings, window/soften smooth.
The problem front left nose is one tiny line that hasn't intersected properly. Remove redraw it and the window becomes separate. There are many other bad lines but that is the one causing that problem.
Thanks Box, I'll take care of that. Do you have any idea how I got all those broken lines in my model? I basically just lofted a bunch of ribs together to get the outer fuselage and then intersected the windows and doors through it. The ribs all had the exact same amount of edges, so I really have no idea what exactly went wrong...
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SU's Intersect is problematic. It almost works.
It does however skip lines, will not intersect a very short face, causes surface flatness issues and tosses in unwanted hidden lines. There seems nothing you can do to prevent any of that.
Keep in mind, Intersect does NOT split the object, as you want to do. It only draws a common dividing line where the 2 objects intersect.
That being said, there are a few things you can do to correct or ease the correction.
First, It is best to draw your helicopter in a half-hull, as a component, then copy and flip its side. Move the copy on axis to join the 2 halves. Make the "dividing" line hidden or at least soft so it won't show later. That will eliminate the intersection operation. Any gaps along the dividing line are easy to spot and fix.
But, say you need to split something along a plane or a shape. (no pun intended) First make that dividing plane/surface a group, so it does not interfere with the objects geometry. Move it into position.
Edit the object and INTERSECT WITH MODEL. It is faster and better to pre-select only the faces that will actually be intersected by the plane. This prevents other intersecting objects to be intersected as well, adding to the cleanup job.
Now you can delete the intersecting face group, but best to wait until finishing fixing stuff.
There are a few things you can do to split the object, either delete the 1/2 you don't want and/or group/comp the part you do want. You can also group/comp the other 1/2.
Now comes the tedious part. Edit the cleaved portion. Hide the rest of model.
Closely examine along the perimeter of the split, looking for line fragments extending or face gaps along the line.
For extended lines, where it has no faces on either side, unhide the model and draw a line from the next vertex to where the line should end, then to the opposite vertex, using the plane group as a reference. 2 faces should form. Delete the line fragment.
Almost always, Intersect will miss only a single segment between 2 points on the split perimeter. Just join them endpoint to endpoint and the missing face should form.
If not, do a very small select lasso on each point to ensure there is not a tiny invisible line fragment, preventing the face. Delete those fragments, and redraw the line. This may also cause other adjacent faces to disappear, and you need to fix them too. Like I said, tedious work.
In many cases, that line may be very tiny, so it may be better to move one vertex (endpoint move) onto the other, eliminating the need for the line, but delete any fragments first.
Surface "unflattening" and extra hidden lines are related. When Intersect does its job, it sometimes cannot put an intersect line in place where an object line is very close to it. Upon cleanup, SU interprets the original objects line as an intersect line, and that causes a surface to unflatten, with hidden lines added to take care of the folding. We are talking less than .001 inch here.
If you need to zoom in very close and get near field clipping, then zoom out and turn off Perspective view. Now you can zoom in as close as you want.
The best way to fix this is to move the endpoints of the line onto the surface of the plane, forcing the face to reform and the hidden lines to hopefully go away. You need to use the MOVE+ALT to move the endpoints, and an axis (red, green or blue) direction. If the plane is not axis oriented, you may have to move the endpoint 3 times (each axis) to get it properly placed on FACE of the plane face.
There are also Pluggins that may help move endpoints onto a flat intersecting face.
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