How to cutaway with 'thickness'?

[ggalen]

I am fairly new to 3D modeling, and I have a question for the experienced Lightwave folks here.

I need to create a blood vessel, and generate a cutaway view.

Polygons have no thickness. I need a 'thick' object.

I could sure use some advice on what works best to do this.

When I "cut out a slice", I still need an "inside" of the vessel wall to exist...can't have an air gap in there.

Ideally I need to animate this in Layout. Would it be a null object clip map on a 'thick object'?

Thanks for any help on what has worked for you in doing this.

[JamesCurtis]

You will need to ceate the blood vessel object with a thickness!

Example: If you have a tube shape with end caps, copy the tube to another layer in modeler and resize it thinner and then boolean cut it.

You can also use a 3rd party plugin called Thickener [check on www.flay.com] which works well too.

[ggalen]

James,

Thanks for the reply.

Yes, I agree. I need thickness.

Would you say the Thickness plug in is the best way you've found for this? Does it leave an air gap between the inner and outer polygons except for the ends?

Wondering how to animate this in layout, still.

[cagey5]

A simple way to add thickness in vanilla LW is to 'select all', copy, smooth shift ([shft] F) to desired thickness, paste.
Merge points.

You may need to do some flipping of polygons in there too...

Done.

[ggalen]

Cagey,

Thanks.

I tried it. Here's the result:



I seem to have air space. Is there a way to do it and have a solid edge?

Otherwise I guess I have to hand connect everything?


Would there be a way to animate the cutaway, seeing the blood vessel "open"? That would be a great effect rather than a simple fade to a new image in the video editor.

[VTA]

If you're going for what you have above, the easiest way is to use the Disc tool. Make a disk whatever length and circumference you want. (I did 3m Length x 500mm x 500mm circumference).

In Layer two create a Disc with a smaller circumference and a greater length (For this I did 4m Length x 450mm x 450mm circumference). Return to Layer one, with Layer two in the background Boolean (Construct Tab) - Subtract. Hit "m" to merge points and there is a tube or artery.

After which, create a box in a third layer and Boolean - Subtract again to get desired effect. Hit "m" again to get rid of extra points.

I attached a 2 pics to show what I mean.
Hope that helps.
-Vincent

[Surrealist.]

Originally Posted by ggalen

Cagey,

Thanks.

I tried it. Here's the result:



I seem to have air space. Is there a way to do it and have a solid edge?

Otherwise I guess I have to hand connect everything?


Would there be a way to animate the cutaway, seeing the blood vessel "open"? That would be a great effect rather than a simple fade to a new image in the video editor.

If you want to animate it you are going to want to do it differently.

What exactly do you want to accomplish in the animation? Let's start there and then work it back. Do you want the cutaway to appear as if having been cut? Do you want it to pull back? Describe what you would like to see as best as you can and then we can work out the best modeling approach.

[cagey5]

You will always have an empty space between the walls of whatever you model. If you are wanting to animate a moving solid edge as a cut surface try watching Mark Dunakins' attached tutorial.

http://www.md-arts.com/clipmapcutaway.htm

[ggalen]

Thanks everyone for your helpful instructions!

As far as the animation, that's a great idea to work backwards from the result.

Wouldn't it look nice to have a line appear and extend, like a scalpel cutting in a line, and then have the artery open sort of like a car's sunroof, revealing the inside, and having the "cut wall" show inner and outer layering like a layer cake?

I will also have a look at all those links in the meantime.

[WilliamVaughan]

Maybe this could help:
http://pagesperso-orange.fr/dpont/pl...n.html#Boolean

[Hopper]

I did it two different ways. Both worked fine and were fairly quick and painless.

1. create your "tube" with plenty of segments (for animating/bending). Take the endcap and use multishift. Inset, then add a shift to the end. Then use the bend tool to get the shape you want unless you plan on animating your bend later in layout.

2. create a spline in the shape you want your artery. Create a disc and use the rail extrude. Copy and paste the end cap into another layer. Size it down a hair or two, then with the spline in the background rail extrude again. Then flip the polys.

Both took less than 2 minutes.

Just keep in mind that wherever you "cut" the thing in your animation, you will need to cap the "walls" between the inner and outer tube.

I would assume the correct model for animating would be "two" arteries placed together, then seperating them out during animation yes?

[ggalen]

Hooperz,

The arteries have an inner lining, called the endothelium I believe, and an outer layer. Well, perhaps more than two layers, but I was just going to show the two.

The animation would reveal the layering on the "cut wall" and the layering.

I would not want to "peel away" the cover, as in a page turning. Just having it slide backwards and away from the scalpel cut works OK for me.

[ggalen]

William,

Thanks! I tracked down this thread for your Boolean Node idea.

Mr. duPont made a plugin.

http://www.newtek.com/forums/showthread.php?t=63221

I'll have to experiment.

[Hopper]

Like this I'm assuming? I simply did the same as VTA was describing. Then copied the tube to a second layer, sized it down to fit inside the original.

[ggalen]

Hopperz,

That looks good!

Now I am thinking about another way, though: How to animate the "cutting in", using a Boolean Node in Layout.