Arch Modeling, Dividing the surface into parts

Hi, everyone…
I was modeling this arch

, I want to divide its surface into parts so I can apply different material to it.Right side lower star is looking good as you can see from picture these are all different surfaces .But on the left side there is a problem lines with are on surface not dividing it.I have check these lines for gaps,redraw the lines but still not working.. Skp File of arch Arch.skp (507.9 KB)

You did draw all the lines with the component open for editing?
If they have been drawn outside the context of the component then you could select them, cut, then open component for editing and paste in place.

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It looks to me as if those edges aren’t on the surface. Since they are on the other side, and the arch is symmetrical, I wouldn’t screw around with fixing the problem side. I cut the arch in half at the apex, delete the bad side, copy the good side and flip it to remake the entire arch.

If Ian is correct that those edges are outside the component/group, select them and cut them to the clipboard. Open the component/group for editing and use Edit>Paste in place to put them inside.

Yes i have draw them after opening the group.

Ok just checking!, Dave probably has the answer in that case.

Is there any tool to check that… I will try that as in my model there are around 30 copy of this arch … hope so it would not screw the whole model… cheers

Check what? That the edges are on surface? If they were, they wouldn’t show as profile edges.

Is the arch a component or a group? If the arches are groups, you’ll have a lot more work to do.

It shouldn’t if you handle it correctly.

It is a component and I grouped it … is that right ??

Profile edges … I don’t know can you tell me more .?

What does this mean? If I was drawing that, I would make the arch a component. No groups anywhere. Then I would copy that component to make the other arches.

I am a beginner so not know the correct way but with the help of you guys learning fast.So it is not right to group a component and why?

Profile edges are the thick edges in your model. Edges that divide faces and aren’t viewed as being on the perimeter of the shape are displayed thinner than the profile edges. If those edges that show as heavy in your third screen shot were actually dividing the surface, the would be shown thin like the other edges dividing the surface. The fact that they are displayed as profile edges is an easy clue that they don’t divide the surface.

Thanks for explaining

Creating a group or component is like putting a transparent wrapper around the stuff inside. There’s no reason to put the geometry into a component wrapper and then put the component into a group wrapper. That would be like double wrapping a sandwich. Although if it is an onion sandwich, double wrapping it might be a good idea, generally that’s a waste of wrappers. One is enough.

Multiple wrappers can lead to errors. If you’ve double wrapped your arch, maybe you opened the group and placed those edges that show as thick inside that wrapper but they are still outside the component wrapper. That would be like opening the outer wrapper on your onion sandwich to add mayo. If you don’t open the inner wrapper, too, the mayo is on the inner wrapper and still not on the sandwich.

By the way, does your mother know you eat onion sandwiches with mayo? :smiley:


I grouped the component so I can not accidently draw a line on an arch.As you said making a component will be enough.I will keep this in mind next time

Make components instead of groups. Then you only need to edit one instance to see the change throughout. Work smarter, not harder.

If you have 30 copies of a group and you need to change them, you need to edit each one or edit one and make copies of it to replace the copies of the old version of the group. This is working harder instead of smarter.

With it closed for editing completely, try to select the edges.

Go into the group and try to select the edges.

Then go deeper into the component and try to select the edges.(they should all be selectable here).

This will confirm which context your edges are, if needed you can then cut them from the wrong place, go fully down into the component. Then edit>paste in place.

Hope this helps.

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No, I mean I have these 30 Arche which are a single component and I know that I have to do edits on one and all will be effected that’s why I grouped them afterward so I can not accidently mess with them

OK. So all the arch components are inside a single group? That’s not all that bad but the group is likely not necessary.

I have done same but now you to get rid of this midline as erasing it will remove the face.

And in that component, there is also a group…:slight_smile: Extra protection. I am so mad tho.