View Full Version : 3d Face on Pline?
3rd May 2003, 08:38 pm
Ok, here's my first dumb question, I'm new to this so go easy.
I've to create a SLR camera using 3d wireframe and apply a surface etc.
The problem is this, although I can apply a face to a regular shape, ie. a tabulated rectangle, I cannot do this to an irregular shape, in my case, for the camera body, 2 in line circles with conecting lines formed into a joined Pline. This must be tabulated or thickened to 56mm high on the Z (World UCS) then a 3d surface stuck on top and base.
The command prompts for 4 points, not the desired Pline shape.
PS, I'm not supposed to be on solids yet (my course says 3D Wireframes first!), but I can do the whole project quicker using the extrude method!
4th May 2003, 08:20 am
A lot of courses start 3d work with surfaces and personally I disagree with this method. Much better results can be obtained for the beginner using solids and then only using surfaces later on. However ....
I sort of get the jist of what you are trying to do.
Could you copy your polyline and put the copy on another layer. Create a region from this polyline and use it for the base and take and move a copy for the top. Look up region in the Help files of AutoCAD.
Th original polyline can be given the thickness of 56mm by going to Modify menu and selecting Properties and when the properties window pops up change the thickness to 56 - ensure you have the polyline selected first before you open the properties window.
You'll need a 3D view on screen to see the results.
4th May 2003, 08:48 am
Thanks for the reply Rob, I'm still none the wiser though. The word "region" in the help files throw up about 140 results!
I understand the thickness in properties, it's just this damn face I can't get. To be honest, I'm not even sure if that's the away I should be doing it, is there another solution available?
PS, Is that little cottage with the sea shells still on the corner of the street in Buckie? Or was it Port Soy? :)
4th May 2003, 09:04 am
If I'm trying to imagine your base shape properly - you have two circles connected by two lines. It doesn't really matter if the lines are tangents to the circles or not so long as they touch both circles.
You would need to trim off the parts of the circles on the inside of the shape - this should leave you with 2 arcs and 2 lines.
Use the Region tool from the Draw toolbar and select the 2 arcs and 2 lines to make into a region. If you have SHADEMODE set to Gouraud then you should see the region has been created.
Think the sea shell house is in Portsoy.
Let us know how you get on,
4th May 2003, 09:37 am
As you said, create a new layer for top and base and original Pline. Thicken the Pline and snap the regions to the Pline.
The only problem is that the base region is only "solid" on the inner face, not the base (make sense?) can I rotate the object through 180 on the X axis to show the face on the base in Iso?
4th May 2003, 10:11 am
If you have a face for the base (the arcs and line region) then use the Copy tool and select the region to be copied to create the top.
When asked for base point to copy from type in 0,0,0 and when asked for 2nd point of displacement type in 0,0,56 to place the top at the other end of the body. In other words you are copying the base up the Z axis by 56mm to create the top.
If you are in shademode Gouraud and you use the 3D Orbit tool to rotate your model on screen it should look like it is solid, but of course it's created from surfaces.
4th May 2003, 09:14 pm
It works ok in shade mode, until I flip it over, then the shading on the base goes. I did it the other way, ie. copy the top surface to the base @0,0,-56.
As it is a direct copy on the Z axis, the shaded surface is on the inside (top) of the thickened Pline, not the base :(
If I could revolve the base region using the X (Longitudinal) Axis, by 180 deg, this should give me the effect I desire, is this a possibility?
All this for a tutorial! :roll:
4th May 2003, 10:50 pm
I'm having some difficulty visualising what you mean Gary.
If you copied the top for the base and did a 3D orbit to view the base you should be able to see it!
I've just tried your camera in a drawing of my own and I think I see what the problem is. I copied a region for the base as well and when I flipped it over in 3D it was not visible. It is there though!!
Here's what I did to make it visible:
Go to Tools > Options > System tab > click on the Properties button next to where it says Current 3D Graphics display > in the top RH corner of the window which opens uncheck the button for Discard back faces > Apply and Close then OK the Options window to close it.
Et voila! :D - your base region can now be seen in the 3D orbit view.
Hope this is what was wrong. If not, could you email me your drawing to have a look at?
4th May 2003, 11:05 pm
Problem solved rob, many thanks, it now shows.
Gary :D :D
Now I may got some sleep tonight, this has been on my mind for ages!
5th May 2003, 07:23 am
Glad we got your problem sorted out Gary.
BTW I really like your avatar - I think it's the best one I've seen so far 8)
5th May 2003, 09:08 am
LOL, yeh it's quite fitting actually....I'm not even on Solids yet ;)
7th May 2003, 08:35 am
Ahhh. I now no how to solve that invisible region prob. Discard back faces.
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