On 4-10-2009 19:12, Orchid XP v8 wrote:
>>> In seriousness for a moment... Do you have ANY FRICKIN IDEA how long 
>>> this took to do?!
>>>
>> Lets see, a pipe is a hollow cone plus a cylinder (2 minutes) add some 
>> csg for the red part (another five minutes). Debugging the loop and 
>> passing of parameters (+5) adding a wooden box (1 +6 for selecting the 
>> right texture), getting the viewpoint right (3 minutes).
>>
>> adding up... something under 15 minutes I would guess. Am I close?
> 
> Have you *tried* doing CSG with SketchUp? You don't just say "please 
> intersect these two things".
> 
> First it takes about 10 minutes to try to persuade it to position the 
> items where you actually ****ing want them. Then you say "intersect", 
> and all it does is alter the polygon mesh slightly. YOU must then, 
> manually, delete the faces you don't want any more. One at a time. You 
> see, any curved surface becomes 25,000 polygons, which you must delete 
> individually, one at a time.
> 
> Just to make things better, I got my CSG slightly wrong anyway, and it 
> took longer to fix it.
> 
> So, now you have one pipe. But I want 23 pipes. So, first select the 
> pipe and ask SketchUp to make 12 copies of it. (Fortunately, there *is* 
> an automatic way to do this!) Now select 11 of those copies, and make 
> them all 5% smaller. Select 10 copies, make them all 5% smaller. Select 
> 9 copies. Make them all 5% smaller. (Are you bored yet?) Eventually, you 
> have 12 pipes, all different sizes. Now the fun part. Copy them, 
> reposition the copy. Mirror it. (Do NOT rotate it as I mistakenly did!) 
> Spent 20 minutes trying to make it line up properly with the existing 
> pipes.
> 
> And, yes, stick them in a box, which takes about 45 seconds.
> 
> I can't help but feel that POV-Ray could have done this radically 
> faster. And the pipes would be *real* cylinders, not 24-gon prisms. And 
> they would be *shiny*!
> 

YOu missed the point, which is simply: you are using the wrong tool for 
this project. If it is to learn sketchup it is OK. If you want to create 
an image, you should reconsider.

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andrel <a_l### [at] hotmailcom> wrote:
> YOu missed the point, which is simply: you are using the wrong tool for
> this project. If it is to learn sketchup it is OK. If you want to create
> an image, you should reconsider.

I haven't played with Sketchup.  What's it good at?
Charles

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> Now, sure, if your window is rectangular, the push/pull tool makes it easy 
> enough to continue. But what if you made a *circular* window? Or some even 
> more complex shape?...

...you need to get a proper 3D CAD program? :-)

Can you not edit the vertex positions of the hole?  I would say in Blender 
just select the vertices or edges of the hole and then translate/scale 
them - I can't believe the same isn't possible in even a very basic 3D tool.

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>> Now, sure, if your window is rectangular, the push/pull tool makes it 
>> easy enough to continue. But what if you made a *circular* window? Or 
>> some even more complex shape?...
> 
> ...you need to get a proper 3D CAD program? :-)

Yeah, figures.

Although, as I said, I've used a lot of 3D editors, and SketchUp is at 
least the first one good enough to make nontrivial objects with. I 
suppose that's something. (It *really* annoys me that it can't do real 
curves though...)

> Can you not edit the vertex positions of the hole?  I would say in 
> Blender just select the vertices or edges of the hole and then 
> translate/scale them - I can't believe the same isn't possible in even a 
> very basic 3D tool.

Oh, you *can* move the individual points or edges around if you like. 
But if your surface is particularly complicated, this becomes 
intractably difficult extremely fast. Nowhere near as easy as just 
moving the shape around before you make the cut.

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Charles C wrote:

> I haven't played with Sketchup.  What's it good at?

Quickly throwing together moderately complex 3D objects. Particularly 
ones with lots of straight lines. (E.g., buildings, machinery, tools, etc.)

There's a bunch of tutorial videos on Google's website. For example, in 
one a guy spends 10 minutes tracing a (very complicated) CAD drawing of 
a building interior. Trace it in 2D, extrude into 3D, cut out a few 
rectangular doors and windows, in about 30 minutes total you have a true 
3D model of the main parts of this house...

It's great fun, but frustratingly hard to do certain things.

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>> Sketckup is a lot of fun, 
> 
> Can it export stuff POV-Ray can use?

It can export data as some kind of XML format. (Apparently it's an open 
standard - I don't know how well documented!) If you wrote a converter, 
then... supposably.

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>> welcome to 3D visual modelling! :D
> 
> *That* is what I want Minority Report gloves for! :-)

Ah, Minority Report. How often does a film come along that makes 
everybody want a particular fictional technology?

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>> ...you need to get a proper 3D CAD program? :-)
>
> Yeah, figures.

Most CAD programs I've used store a tree of features/actions used to get to 
the final shape, this means you can go back and edit any of those previous 
steps.  In your example the shape you drew to make the hole is stored 
exactly as that in the file, then of course you can edit it and see the 
result.  I saw partly this kind of behaviour in 3D Studio Max (or whatever 
it's called now), in that you could keep two separate objects and see the 
intersection of them, but most mesh editors just store the mesh and no extra 
data.

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> Most CAD programs I've used store a tree of features/actions used to get 
> to the final shape, this means you can go back and edit any of those 
> previous steps.

That sounds like a more logical way to work.

Presumably CAD also allows you to do things like "find a point 3/5 along 
the length of this edge". SketchUp automatically marks the 1/2 point for 
you, but for any other point you've got to get out a calculator.

Other annoying SketchUp features include the lack of the ability to 
manipulate a circle be its center. (Because, of course, once you've 
created it, it's not a circle any more. It's 24 unrelated edges.) And 
the best feature of all is the way surfaces "stick" to each other as 
soon as they touch...

> I saw partly this kind of behaviour in 3D Studio Max 
> (or whatever it's called now), in that you could keep two separate 
> objects and see the intersection of them, but most mesh editors just 
> store the mesh and no extra data.

Yeah. How SketchUp does intersection is that you line up the two 
objects, press "intersect", and then delete the geometry you don't want. 
Manually. Which, for curved surfaces, takes a really long time. 
(Because, naturally, those surfaces aren't really curved. Stupid 
idea...) Also, you can't delete any item smaller than a certain size on 
screen. You have to zoom in first. And the minimum size is significantly 
larger than you'd expect.

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> Presumably CAD also allows you to do things like "find a point 3/5 along 
> the length of this edge".

AFAIK there is not usually any automatic way to do that, you'd just need to 
add a formula to one of the point dimensions that says something like 
"Edge1.Length * 3/5".  That way, whenever the length of that edge changes, 
the point is always fixed 3/5 of the way along.  You could then draw some 
geometry referenced to that point, then of course that would all move with 
the point too.  It gets a bit like POV, where you can just define a variable 
for something like "screw position", and then drive lots of other features 
like holes and cut-outs in lots of parts from that one variable.  The 
benefit of this is when your customer says "ok we need that screw moved 
1.2mm" it only takes you a few seconds to update all your parts rather than 
an hour or two.

> the best feature of all is the way surfaces "stick" to each other as soon 
> as they touch...
...
> Also, you can't delete any item smaller than a certain size on screen. You 
> have to zoom in first. And the minimum size is significantly larger than 
> you'd expect.

I would expect there would be settings for these sorts of things?

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