Problems with modeling from Acad drawings
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@honoluludesktop said:
What's a locked layer?
you can hide a layer - maybe they mean this? i just group it though.
also i thought there was a plugin somewhere maybe called StrayLines that was a big help for this. MakeFaces is good for dwg imports too.
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An old trick I use is to never use the imported linework except for inferencing. I place the imported drawing some way up from my "work plane". Then I draw a large rectangular face. Then I start modelling with the rectangle or line tool, placing it on the face until the "on face" tooltip appears, press down Shift, and start clicking away at the points in the imported 2D component. I also try to keep an eye on axiality to avoid the ******* small deviations that try to creep in (yes, there are sloppy drafters in my colleagues, and I am sometimes one too).
Anssi
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Good ideas, all. Am trying out some at this time. Thanks.
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@honoluludesktop said:
What's a locked layer?
The layer is visible but locked. You cannot edit it's contents in any way.
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I can tell your working with architectural drawings. I'm going to say what most will not, and that is that architects are some of the absolute worst when it comes to drawing things precisely in autocad drawings. Snap to grid, ortho on and precision set to whole inches and over ridden dimensions everywhere are just a few of the issues we have seen in the majority of architectural cad files I have had the displeasure of dealing with. Why? I don't have any idea, but it is unfortunately more often the rule instead of the exception, and I would get fired for drawing things that way.
I apologize to those architects that don't do this, if you don't, be happy that you are the exception.
If you are one of those people that do this, don't bother making a defense for it, I really don't mind, we make a huge amount of money creating shop drawings and putting in change orders when the things specified are a physical impossibility and we get to charge to make it work.
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I think in the context 'locked instance' was meant rather than 'locked layer' - you can't lock a layer in SKP [you can in CAD] BUT you can 'lock' a SKP's groups and instances so that they can't be moves, deleted or changed until you 'unlock' them...
On the topic of rubbish CAD drawings... I once had the unenviable task of doing the construction drawings and documents for a maximum security prison originally designed by one of the governments most respected consultants and signed off on a set of design drawings and a scaled wooden model. We got the CAD drawings [plans, sections and elevations] and set about working up the scheme. I realized that you couldn't form the complex hipped roof as they had shown on the roof plan and elevations - there were two eaves heights between two main block 'wings' with a connecting 'arm' - there are rules about prison roofs having no flat or hidden areas, slopes, non-grapple-ability etc... I was exasperated! After a lot of brain ache I came up with a solution that worked to everyones satisfaction... We had never seem the physical model because it was on someones desk at the Home Office. When I discreetly raised the balls up with one of their architects she said, 'Oh yeah, we knew the roof didn't work when we came to make the physical model and had to fudge it - we didn't have time to change the drawings...' [they also didn't have the courtesy to tell us either]
IF they had made a simple SKP model it would have showed them at an early stage that the 2D CAD just didn't work - it is possible to check that your 2D CAD DWGs all align and work in unison BUT too difficult for many to bother to do -
I was just looking at this issue on importing AutoCAD to Sketchup and I wanted to find places where there was discontinuity in connecting lines. Well it turns out it looks like sketchup really has a problem with AutoCAD curves, and this seems to be where most of my problems arise. I saw that where straight lines meet a curved arc, the lines almost rarely meet. However I went back and looked at the ACAD file and the line is definitely hitting the curve. I know Sketchup has never been very good with curves so this must be one of the main issues with importing, besides bringing in imprecise ACAD drawings.
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Assuming the curves are arcs/circles and not part of 3d faces then there's my tool to increase the number of segments from the default 24s etc, this will reduce the gap... and if you are lucky it might even even close it, if a node is coincident with a line's end.
Thomthom have some great tool to tidy-up / enhance CAD drawing [Edge Tools, Plan Tools etc] - useful for closing small gaps, sloppy drafting errors, simplifying etc, which will be useful to you.
Use the 'Plugins Index' red button and then a browser-search for us as authors... and/or by keyword like 'segment' or 'edge' or 'plan'... follow the download pages' instructions - I know that some of tt's tools need a second download of helpers = usually TT_Lib2 linked from his page... -
@tig said:
I think in the context 'locked instance' was meant rather than 'locked layer' - you can't lock a layer in SKP [you can in CAD] BUT you can 'lock' a SKP's groups and instances so that they can't be moves, deleted or changed until you 'unlock' them...
Funny! I have done many security layouts for jails and the one architect never doing a jail before, had skylights over the cells. Real glass, no bars, skylights.
He cut pasted from a motel project.
Cut & Paste is a problem no one mentioned. I see many "Boiler plate cut-outs" drawing not even related to the project on drawings. -
@drafter x said:
I can tell your working with architectural drawings. I'm going to say what most will not, and that is that architects are some of the absolute worst when it comes to drawing things precisely in autocad drawings.
I beg to differ - engineers are the absolute worst at snaps, trims, etc. Not to mention there redlines on drawings...
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This is a very good post.
I come from the GIS (Geographic Info Systems) world. What we typically do when creating maps is construct a "topology". This is "cleaning up" your map. So, snap nodes, trim lines, snap line, remove duplicates. Very time consuming, but there is a decent work flow to getting your topology to work. You can run the various python scripts to find errors and then zero in on them and correct it. I believe in the 3D world some people will typically say the "geometry must be manifold", which to me is synonymous with "creating a topology".
My 2 cents,
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@gisdude said:
@drafter x said:
I can tell your working with architectural drawings. I'm going to say what most will not, and that is that architects are some of the absolute worst when it comes to drawing things precisely in autocad drawings.
I beg to differ - engineers are the absolute worst at snaps, trims, etc. Not to mention there redlines on drawings...
Agreed. Although many Architects are just as guilty.
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