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New "3D line weight" attribute


Ken

Question

One of the inherent problems with getting nice-looking viewport elevation drawings for contract documents (construction drawings) is that the line weights look crappy. As a result the whole drawing looks amateurish, artless, sterile -- reading like the author didn't really understand the importance of each building component shown.

What if...

What if we had a new attribute for hybrid or 3D objects to control their "3D line weight" separately? All objects can keep their "regular" line weight in top/plan view. Walls are the prime example, where they should appear heavy in a floor plan, but would be nice if they blended with other thin lines in side view (hidden line render).

Currently the Line Weight Scale factor in the Advance Properties of a viewport changes the entire viewport but not individual objects. Perhaps something like that but for individual objects might suffice.

A more comprehensive and further-reaching improvement is something that can intelligently assign heavier lines to edges that are closer in view... then maybe also lighter lines to flatter objects... etc.... but that's probably asking too much.

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I agree this is a problem.

Having been taught (and teaching) the importance of the "correct" use of lineweights on different parts of objects to communicate the intent of the drg, it's disturbing to have hidden line views with "uniform" line weights.

Using Convert Copy to Lines is a sort of work around, but defeats the advantages of viewports, and of course any curved objects get smashed.

The technology exists (in things like the Fillet edge tool) to select individual edges of 3D objects, so it should be easy to use that to assign line weights to individual edges ;-D

HA!......... "EASY!!"............

I can hear the Engineers grinding their teeth from here. ;-)

' Would be much better though.........

cheers,

N.

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I've been told Archicad has this ability so i'm sure NNA's engineers could manage it.

Archicad allows control over line thickness depending on depth from viewing point - i.e closer elements have thicker lines.

It's definitely something i would like to see in VW

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Ken, this is a provocative (in a good way) idea. It probably represents the greatest challenge a CAD software engineer could hope to face, since the ideal line weight in an elevation is not uniform for all edges of the standard 3d object, and even changes depending on point of view. Take the simple example of a cube. In an artistically effective elevation, the corner facing you has a lighter line weight than the corners that outline the object against the background. Rotate the cube, and that same corner now becomes part of the outline.

In thinking about this I would start by trying to conceive of a way to accentuate the boundary between object and background, without necessarily defining a line weight attribute of the foreground object.

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the ideal line weight in an elevation is not uniform for all edges of the standard 3d object, and even changes depending on point of view.

That's why I think manual control would be better than "automatic"

Automatic has all the problems you outline, and you're still at the mercy of the algorithm that defines it. You may well still not get what you want.

N.

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I'd be happy just having control over wall line weights so that I can have them looking as they should in Top/Plan View, and having the line weights I want in 3D generated views like elevations and perspectives.

For example 0.35 lines for the perimeters of the walls look okay in Top/Plan View but look awful in the 3D elevations views. What is needed is the ability to choose a separate line weight for the 3D views so that the elevations can be tailored to achieve the desired look. This concept may need to be extended to other hybrid objects as well so that the drawing can be made readable by having different 3D line weights for different objects.

Maybe the concept of Depth Range could be incorporated into Elevation Views as well so that lines beyond a given depth from the Viewing point could be assigned a different class so that they could be given a different emphasis (eg. greyed with a lighter line wight) so it is obvious that they are in the background.

Edited by mike m oz
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I've heard the Revit uses a Course, Medium, Fine approach to controlling lineweights based on what you need to show in a certain drawing. Something like this may or may not help this issue.

It is probably a lengthy setup process if not already done, but we have started using classes for all our stuff in plan. Our wall class could have a viewport specific override for line thickness to control the apparence in an elevation viewport in VW right now.

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Adding the capability to override the plan wall lineweights for elevations would be a significant step forward just by itself.

In Plan Views the protocol is to have your walls drawn as if they are horizontal sections through the walls. Therefore the wall outlines are usually drawn with a relatively thick line. In Elevation Views the walls need to be drawn with a thinner line because they are no longer in section. Having the wall perimeter lineweight used to draw the walls in Hidden Line Rendering Elevation Views does not provide the correct appearance. Or to put it more succintly the walls in elevation views should not look as if they are in section.

Edited by mike m oz
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Adding the capability to override the plan wall lineweights for elevations would be a significant step forward just by itself.

Mike, I'm embarrassed by the modesty of your ambition. Shoot for the sky! Demand the world! ;-)

OK I'll be serious now.

Kenneth has highlighted a problem with Hidden Line renders that extends far beyond mere Architecture.

Really it's far more than making the drawings look "nice"; it gets to the core purpose of Technical Drawings: to convey information. The selective use of line weights has always been part of that process.

For the Engineers to expend effort on a "Wall specific" solution would be a "waste of effort", and missing the point. It's the entire Hidden Line rendering process that needs working on and the wall problem should be seen (and dealt with) in that context. If you want an "Architecture based" example; Last semester I had the Interior Design students learning 3D modeling by producing custom Kitchens. The viewports elevations of their models suffer from exactly the same sterile anonimity of linework as is being discussed here. 2 modes of wall display aren't going to help, it's the hidden line render itself that's the problem.

just my 2c

cheers,

N.

PS "mere Architecture": yes; I was teasing ;-)

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How about introducing another edit option in the Edit Viewport window. Perhaps between Annotations and Crop there's another button for Line Weights.

Once inside, each visible line (or polyline or rectangle), when highlighted, would be editable in the OI or in a local pop-up for its individual line weight scale factor -- including zero.

Including zero would be the key.

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Nicolas, the problem with manual control, which is otherwise a good idea, is that applying it to complex assemblies of objects over and over again could be time-consuming. I agree with others that the whole hidden-line rendering concept needs a thorough review. Two important issues come to mind:

1 We need to have lines where two solids intersect, but only where there is a significant angle of intersection (i.e., not 180 degrees like two walls butting ends together).

2 We need to be able to create emphasis at edges of solid objects, where they are seen against more distant objects or background.

I think there is a way independent of object attributes to achieve both goals. My idea of a good (automatic, but controllable) method for problem 2 is to have the program recognize where there is space between the edge of an object and something in the background, and to apply a heavy line to that boundary, more or less thick in proportion to the distance between foreground and background objects. This "corona" outline would be a rendering effect, not a line object. The outline could be an option selected for hidden line rendering, and the degree of heaviness, etc., could be set by controllable parameters in a hidden line rendering options dialog box.

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Nicholas - I do want what you blokes are suggesting needs to be done, though I am wary about another layer of complexity being introduced into the program.

In the short term though (next release) I would like the 3D wall lineweight issue fixed. Therefore I am suggesting that NNA introduce a solution for this one problem so that elevations produced from the model can look as they should. All it needs is the introduction of a 3D line parameter into the Wall Styles dialog box so that we can define the lineweight for walls in 3D separately.

PS:

- I do know you can scale lineweights in the viewports, but this scales all line weights and therefore does not produce a good visual result.

- Having to compromise the Plan View to get the Elevation views looking okay is not an acceptable workaround. We need to be able to draw both correctly.

- With some of the things like this that slip through the net I sometimes wonder how many of the Beta testers are people who actually do real work on real projects.

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I believe that Sketch-up also has "fore-aft" line wt control. More important than "lines closer are thicker" is the concept of shallow vs. deep relief in accurately showing the depth of an edge condition.

I don't know if its just me, but I can't get the polygon by lasso to work right in VPs and SVPs. This is a work around that I use to good effect in Design layers.

Control of 3d linewts would dramatically reduce drafting time for me! I'm a perfectionist when it comes to using line wts to accurately and artistically describe elements in space. Maybe its cause I'm just old enough to fondly remember co-workers commenting on my good "hand."

cheers, mmm

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I agree that line weight for elevations is not as simple as "lines closer are thicker." In many cases lines more distant should be thicker than certain lines closer to the viewer - when the former are outlines and the latter are corners, to cite the most common example.

If NNA can conquer this problem and give us a really smart and easy-to-apply lineweight rendering tool, VW would have another leg up on the competition.

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