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How do I find where multiple three dimensional shapes extruded at different angles intercept?

Oct 20, 2013 1:55 PM

I created two three dimensional shapes that are extruded at different angles.  How do I 1) move one of the shapes so that it intercepts the other shape and 2) find out where the two shapes intercept each other?

 
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    Oct 20, 2013 2:40 PM   in reply to jbbbbb

    How did you create them?

     
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    Oct 20, 2013 3:36 PM   in reply to jbbbbb

    Illustrator is no 3D application. There's no 3D world. All of these objects exist in their won "world". So you need to use classic perspective construction.

     
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    Oct 20, 2013 3:53 PM   in reply to jbbbbb

    Illie’s 3D effects are rubbish. You can’t create a scenario of multiple shapes.

    You can extrude 3 shapes simultaneously but they will all have the same extrusion and a common vanishing point if you use perspective.

     
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    Oct 20, 2013 4:08 PM   in reply to jbbbbb

    What is the least expensive way that I can ????? the type of 3D effects that I need?

    Depends on what you want to ????? and what a ?????ing costs.

     

    How complicated is the object that you want to ????? ?

     
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    Oct 20, 2013 4:45 PM   in reply to jbbbbb

    You mean something like this, seen from the side?

    Picture 1.png

    If so, the answer is ‘with considerable difficulty and a good deal of anguish’.

    Like I said, Illie’s 3D effects are unsuitable because you can’t make a 3D scenario of more than one object at a time.

    If you are reasonably proficient at old-fashioned 3D construction using vanishing points etc. it’s not a huge problem, but I would really recommend a decent 3D programme if you want computerized help. It would have been a sinch in Adobe Dimensions but this programme has long since been discontinued with the consequent wailing and gnashing of teeth.

     
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    Oct 20, 2013 6:48 PM   in reply to jbbbbb

    I'm not sure if I understand what's in your mind, these things are best communicated by showing a sketch.

    Anyway, I made  examples with a few possible  intersections. As others said 3D in Illustrator is per object and is limited to extruding a profile along a straight line and the only modification possible in the 3D space is applying predefined bevels. So, anything more complex has to be 3D look made with 2D tricks.

    I made the intersections by stacking different objects to look like one cylinder passing through the pentagon. These examples were relatively easy to make, but you have to rely on you sense of 3D and rotate, position, and scale interactively the objects until they look OK. Stacking objects to look like they intersect is easier if the intersection surfaces are flat like the two examples on the left. For the two copies of the example on the right where the cylinder intersects the edge of the pentagon I made a clipping object hiding part of the cylinder to make it look like it is 3D as shown in the last example

    Capture.JPG

     
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    Oct 20, 2013 11:27 PM   in reply to jbbbbb

    3D Booleans require a 3D program. If you want to generate it as vectors, you would have to use a CAD program and then generate a custom projection from teh result whose curcves you can export for further manipulation. Anything you can do in AI natively is just an illusion. Whether the techniques suggested by the others satisfy your needs will depend on teh specific situation of course...

     

    Mylenium

     
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    Oct 21, 2013 3:37 PM   in reply to jbbbbb

    Jbbbbb,

    incredibly even this big image is still not enough for me to figure out what kind of intersection is in your mind The cylinder can intersect the pentagon where the star is on your image at any possible angle and the cylinder can be with any possible thickness in relation to the pentagon which will cause different intersection.

    Isn't it in principle the same as the last case (right side) in the image I posted before but just the pentagon facing in the same way as in your image?

     
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    Oct 21, 2013 4:09 PM   in reply to emil emil

    emil, would something like this be more helpful than more explanations?

    cilynderThruPentagon.png

    made with paint, (pencil and paper works as well)

     
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    Oct 21, 2013 5:59 PM   in reply to CarlosCanto

    yes Carols, this is what I had in mind when I said, these things are best communicated by showing a sketch 

    and your drawing is basically the same thing as shown in the first example of my image

     
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    Oct 21, 2013 6:03 PM   in reply to jbbbbb

    Jbbbbb,

    there are two implementation system of the z axis, one is oriented perpendicular to the viewer's eyes (or camera) and the other is oriented to what a vertical line in 2D is. The two systems are options in many 3D programs with one or the other being a default. After that you have to specify which z axis, the axis of the world or the pentagon object which is already turned -35 degrees along x.

     

    jbbbbb wrote:

     

    I don’t know if the type of curve that I am looking for is the same as the one that is shown in your fourth image.

     

    From your input so far it seems to me that this is the angle for the cylinder in relation to the pentagon you are looking for. What remains to be figured out is how the pentagon overlaps the cylinder when the cylinder passes through it. Is it completely covered by the pentagon  or some part of the cylinder is sticking outside. If the star on your image is the point where the center of the cylinder is then one side of the cylinder will be sticking out of the pentagon and when viewed from the angle shown in your image that will be at the back and depending on the thickness of the cylinder it may be only hinted in the image.

     

    edit: Oh, you added an image while I was typing. OK, that's the same as my forth image in the examples, but your cylinder is wider than the pentagon. If that's the way you want it, yeah it is a challenge making it in Illustrator.

     
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    Oct 21, 2013 6:26 PM   in reply to jbbbbb

    Provided the cylinder is wider than the pentagon, here's what can be done, basically using the same thing like the fourth example from my previous image. You hide part of the object in front to show the object behind. The selected paths are hiding part of the cylinder to show the pentagon behind giving illusion of intersecting.

    Capture2.JPG

     
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    Oct 21, 2013 6:50 PM   in reply to jbbbbb

    To make sure I have understood your last image correctly it could be that you tried to make a or b on the image below but you didn't make is as clear. I took that you were trying to make a but it could be b you had in your mind. If it is b it is much easier and it is the same thing as the fourth image in my first example just oriented like the last example with making a. In general the approach is the same, hiding parts of an object to look like intersection.

    Capture3.JPG

     
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    Oct 21, 2013 7:37 PM   in reply to jbbbbb

    I'm not sure if I am going to be able to complete this image in SketchUp.

     

    What part of this are you having so much difficulty with in SketchUp?

     

     

    JET

     
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    Oct 21, 2013 8:43 PM   in reply to jbbbbb

    OK, now the angle of the small and larger cylinder in relation to the pentagon is clear. So you want two cylinders? You are showing the small cylinder cut as if it is sitting or slightly stuck on the edge of the pentagon. If that's the way you want it - this part is easy in Illustrator put the cylinder in front of the pentagon. About the larger cylinder the question is what part you want remaining from it? Do you want to be cut as if the pentagon was a knife going through it? And do you want the cylinder to be hollow or solid?

     
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    Oct 21, 2013 8:47 PM   in reply to jbbbbb

    I don’t want the pentagonal face of the prism (shown in the image below) to be blocked by the larger cylinder. Is there a way to cut part of the larger cylinder?

    Are you saying you want to see the section plane?

     

     

    JET

     
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    Oct 22, 2013 12:17 AM   in reply to jbbbbb

    jbbbbb wrote:

     

    I don’t want the pentagonal face of the prism (shown in the image below) to be blocked by the larger cylinder.  Is there a way to cut part of the larger cylinder?

     

    Based on the image you provided and your explanation, I understand this. With possible difference the big cylinder to be hollow and not solid.

    02.jpg

    I made it using a 3D program to visualize it better but the 3D effect in Illustrator is not going to render anything like that.

     
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    Oct 22, 2013 12:27 PM   in reply to jbbbbb

    The program I have is not free but Blender is an open source 3D program that some claim is equal and in some respects better than the heavy weight commercial 3D programs. The 3D programs can be considered as two types, some are CAD oriented for design and precision and the other type are more artistic oriented for visualization, rendering, and animation. For simple stuff like your example any 3D program that have some rendering capabilities should be able to handle this. I haven't used Sketchup which you appear to be using but out of curiosity I searched Google for "google sketchup examples" and at first look it appears that it may be able to render something that may work for you.

    The biggest problem with any 3D program especially the higher end ones, is that they have very steep learning curves and may take a lot of time before being able to create decent renderings.

     
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    Oct 22, 2013 12:46 PM   in reply to emil emil

    Just wanted to add that If you need to create such things occasionally and showing them from one point of view, Illustrator can be used to create 2D artwork representing nicely 3D objects. Of course if you are not very experienced with Illustrator it will take some time learning it more in depth before you can create easier but the learning curve is nowhere near what it would take to learn a full featured 3D program.

     
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