Hollowing out an object?

[Heng2001]

I am new to using vector works and am use to selecting all the surfaces of an object and shelling the entire object to hollow out the center. I do not want an open face, just the interior hollowed out. Is there something im missing? I believe I have tried everything. Thanks for the help.

[Ray Libby]

Maybe create another solid representing the hollow part and subtract solids?

[Pat Stanford]

Do you need thickness to your walls? If not, the convert to 3D polygons or Convert to Mesh will give you just the surface of the object.

If you want a cavity within an enclosed object, you will need to duplicate, scale down and subtract a new object from the original as Ray suggested.

Pat

[Heng2001]

yes i need thickness to the walls. i get an error saying that i am trying to create an empty solid object when i try to subtract a scaled version of the same solid. this program seems to be very inconsistant also. at one point i had the option to set my x,y,and z scalars and now i dont??

[Pat Stanford]

You probably were trying to subtract the larger object from the smaller rather than the other way around.

Once you select both objects and execute the Subtract Solids command, use the arrows on the dialog box to select the object to subtract the other objects from.

Pat

[Heng2001]

yeah, you were right, thats exactly what i was doing. my new problem is that if i try scaling an asymmetric object that is an extrusion, it wont let me. i guessing because its an extrusion. so i try the modify>convert>generic solids function and it wont convert to a solid which i think would allow me to scale the object asymmetrically. thanks alot for the help.

[bc]

So in a blank file, if I extrude a square into a cube and then:

duplicate

scale 75%

select both

subtract solid from larger cube

slice in half and rotate for viewing

I DO get a subtracted solid which reads in wireframe but renders solid as if unsubtracted. So we can't get there from here? Some times, as I am rotating it, I can see a ghost of a line which seems to be one of the edges. Other solid subtraction operations that are non-concentric non-interior are working. Anyone else?

Edited May 8, 2008 by bc

[mike m oz]

For symmetrical objects model one half, making this half hollow using the Shell Solid tool from the Modelling palette, with the hollow end at the join plane. Mirror this half and use Add Solid to combine the two halves into a single object with a hollow centre.

For none symmetrical objects create two separate halves in a similar fashion and then use Add Solid to combine them into a single object with a hollow centre.

[bc]

OK thanks MIke, I see the workaround, but my question for anyone is why can't VW perform this operation?

[mike m oz]

I've looked at a few tutorial movies for other modeling programs and most of them seem to use the halves technique. Particularly where parts are symetrical.

I just tried the Solid Subtract method described further up in this thread. When I split the hollow object using the Split tool the resulting objects are correct for me so I'm not quite sure why you are not getting the correct outcome. Perhaps attach a file with that object in it so others can see what is going on.

[bc]

OK here it is.

[mike m oz]

I can't figure out why it doesn't work for you. Initially I thought it may have been because the base polygons were unfilled. But even if I start from scratch in your drawing it will not work.

If I start in a fresh drawing however it works every time (VW 12.5.3 Mac).

[bc]

Well I started with a fresh file too. Just now I restarted, opened a new file and even used the standard architect workspace. So if it's not VW 12.5.3, a corrupted file or workspace in 12.5.2, I supposed I should try the final build. I forget why but for some reason I decided to wait when I saw on the board that some people were having problems. I'll try the install 12.5.3.

Thanks, Mike....for literally burning the midnight oil.

Wait, I just downloaded your file Mike and I can get it to work with yours. Maybe I have a corrupt template? I'll check that out first.

Edited May 8, 2008 by bc

[Pat Stanford]

I think I have it figured out.

If you use the split tool, it creates a Solid Section. The sectioning plane is always solid. If you want to show the inside, you need to do a solid subtraction instead.

Pat

[mike m oz]

Split works for me Pat, except in bc's drawing.

[Pat Stanford]

Mike,

I thought it did for me yesterday also, but it sure won't today. I have even quit and restarted VW about 6 times just to make sure.

I did some more testing. I think it is a bug in the Solid Section.

In VW2008 SP2 on the Mac.

I draw a square and extrude it. Duplicate it. Scale the duplicate to be smaller. Select both extrudes and Subtract Solids. Use the split tool to cut across the cavity. I get two Solid Sections that render with the "section plane" as solid.

Do the same thing and move the "cavity" off-center. Solid section plane.

Move the "cavity" so it breaks one of the walls (open object instead of hollow). Sections show the cavity.

Use the Sphere tool. Duplicate/scale/subtract/split. Section planes are correct in showing cavity.

Use the Extruded Rectangle tool. Duplicate/Scale/subtract/split. Section plane is solid.

Sphere inside extruded rectangle works correctly.

Now for the really strange part.

Rectangle, extrude, duplicate, subtract, split. Section plane is solid.

Enter the solid section and the subtraction. Move the "cavity" so it breaks a wall of the outer object. Exit Subtraction, Exit Section. The Section Plane display correctly.

Pat

Edit again so the "cavity" is completely inside again. Now the Section Plane display correctly.

Pat

[bc]

Say Pat could you repeat that?

Just kidding. Seriously though, I just upgraded to 12.5.3(80532) and the problem persists. And from Pat's exploration I say it is a bug.....except Mike CAN do it and I CAN do it with Mike's file.

[Pat Stanford]

Curiouser and Curiouser.

I just tried Mike's file and as you say, it works there.

I then created two new files. One using my normal template and one using a blank document. Does not work in either one.

I then restarted VW and reset my preferences. Tried again. Still does not work.

I don't know what is different between what Mike is doing and us.

Actually, I thought I had the same results as Mike yesterday, but after I tried your file today I have seen exactly the same results.

Pat

[Pat Stanford]

Mike,

If you are really brave, can you try bc's file and see if after running it you can still gt the correct behavior in a new file?

Thanks,

Pat

[bc]

Pat: "Actually, I thought I had the same results as Mike yesterday, but after I tried your file today I have seen exactly the same results."

Could it beeeeeeeeeeeeeee....................SATAN?

Surely Mike's in bed by now. He mentioned earlier he couldn't do it with my file but that it worked every time with his new files. Any NNA techies have a comment?

Thanks Pat, hope I didn't screw up your VW with that file...

[Pat Stanford]

I just tested this on a different machine I have here. It is a completely unmodified VW2008 SP2. It does not even have any customized workspaces.

Rectangle/Extrude/Duplicate/Scale/Subtract/Split results in a solid clipping surface.

Even more evidence it is a bug.

Edit the Solid Section and the Solid Subtraction and then exit them and it draws properly.

Now the question is what is different about Mike's setup that lets it work properly?

I have tried all of the 2D and 3D converstion resolutions and turned Quartz on/off. Anti-Aliasing on/off and Vector Caching on/off. No difference.

Anyone have any other guesses?

Pat

[mike m oz]

Pat, I get the same result as you in VW 2008 (SP2). It works correctly in VW 12.5.3 though. I wonder why the difference.

It doesn't seem right though. If you section a solid with bits missing it should show the holes rather than fill them in. I'll bug report it.

PS

This is getting weirder. I just moved the two halves of my VW 2008 cube so they were centred exactly on the centre of the page and all of a sudden the left half is hollow but the right half isn't. Something isn't right here.

Edited May 8, 2008 by mike m oz

[mike m oz]

This is geting even weirder. I just went back to VW 12.5.3 and tried to confirm that it worked in VW 12.5 and now it won't work, and yet as my posted image further up shows I was able to do it last night. Unfortunately I didn't save that file. I am totally confused now.

[Pat Stanford]

The file you did yesterday is available for download higher up in the thread. It works as you stated even under VW2008.

Very strange.

Pat

[bc]

I think I've created a monster! Sorry guys.

How about Heng2001? Are you able do do it? Anyone else?

Perhaps the bug techs will figure this out? Won't do me much good being in 12 right now but you guys will benefit.

Thanks Pat and Mike

Bradley