3D Newbe Help
After many years in 2D CAD I am venturing into 3D. What I am having trouble with is the very basic tasks.
Viewing the model is OK and I can 3D rotate OK as long as I know where I am.
I am creating W-Beams and Angle Iron from the library. The base of my project is at 0,0,0 and I am oriented so that TOP is my Plan View orientation.
This way Z changes will lift or extend things off the ground.
That seems to be working well.
The main issues I have is aligning parts relative to other parts. For example I need to butt a smaller W shape into the web of a larger W shape.
What is the best method of aligning that smaller shape?
Also do you recommend a basic book or video for the beginner. Most videos assume you know more than I do.
Thanks
Comments
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Others may offer better advice. But, when assembling parts I tend to think about and use constraints as the thing would exist in the real world. So in your example you have the end face butted up against the side face of the other parts. Using the coincident constraint, fixes these 2 faces to the same plane in space. To completely constrain the 2 part together you need to add at least 2 more constraints. Now there is multiple ways you could do it, but a simple approach would be to use distance constraints. Adding a distance constraint between 2 pairs of parallel faces on each part perpendicular to each other. You could add a suitable dimensional constraint center one beam to the other. Another distance constraint between the end face of the vertical beam and a side face of the horizontal set how far along its fixed.
The important thing is when adding constraints make sure you are selecting faces not edges (unless you intend that) other wise you tend to end up with axis of rotation on the edge and would need additional constraints to fully fix the parts.
For part that bolt together I would use a concentric constraint on the holes, a coincident constraint on the mating faces. But the nominal positions of the features have to be precisely defined otherwise the constraint will fail. Which forces you to model accurately which is no bad thing.
Hope that helps some.
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Thanks for your reply. I'll do some reading on constraints so I can put your advice to work.
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It takes a while to get a good understanding of constraints, regardless of what CAD program you are using. It helps a lot of have someone coach you. But, if that is not available, then this forum is very helpful. Just post your problem drawing, asking for help, and giving any detail you can. Also, try to remove as much as you can from the drawing, but still show the problem, can help to make it easier to trace it.
Historically, in some of the parametric programs, it was important to prevent redundant constraints. I think this was because once you rotate or translate an object, the precise coordinates of all its geometries are slightly changed, because there are rounding errors. In the real world, something that is 0.000000000001" off is of no consequence, unless you are arranging atoms. But if a CAD program wants something exactly equal, that 12th decimal place does matter. However, in more recent years, at least SolidWorks has become more tolerant of redundant constraints.
So, what is a redundant constraint? Lets say, you have a mounting plate with 2 holes 10" apart, and you attempt to constrain a mating part to those two holes. If the 2nd part has to rotate 5 Deg for those two holes to match, then those two holes are unlikely to be precisely 2" with 12 decimal places of accuracy. In the past, at least, the way to approach it was to mate one pair of holes using concentric, and ignore the other pair. Another type of mate would have been necessary, perhaps two faces set to be parallel, or at a known angle.
I have an older v14, and actually gave up on the 3D mechanical part of the program, because I was running into a lot of problems. But, perhaps the current version has improved enough to be usable.
-Joe
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Thanks Joe for the Heads Up.
I'm sure I will be posting problems in a few days.0 -
In my opinion it is strange to use 3D constraints when creating a static assembly. The more common approach is to manipulate the UCS (e.g. work with the lock feature of the DUCS) and/or use temporary tracking points. But I don't create 3D models on a daily basis so I may be wrong.
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I agree with Roy. I do a lot in 3D (sometimes just for fun!) and only use constraints on static assemblies when I'm doing something parametric (e.g., this example).
For the most part using ordinary snaps, snap tracking, temporary tracking points, or non-printing construction lines is sufficient. There are other tools available, such as Project Geometry as Jason Bourhill explains here which can really be a big help in some cases.
Strongly recommend browsing through the available tutorials and follow along on your own system.
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Thanks, the example is quite good. Another example although using AutoCAD is long but very basic.
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I saw the Project Geometry tutorial, in fact, I have watched it twice.
I have watched many over the past three weeks as I attack this new 3D environment in my spare time.
The one you posted may have been missed by me because it was sheet metal. Perhaps I'll revisit those.
With no real interest in sheet metal at this time, I skipped those.0 -
In all the tutorials I have watched many do not show the actual command used to move and align parts as they are concentrating on the bigger picture. At my level, I need the very basics of the process. One I say a week ago used some command to align faces of two parts but it was not the 3D Align command. Just clicked the faces and one part moved to the fave of the other, I think it was not a constraint.
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OK working with my first 3D assembly, I find that when a part (W10x22) is copied it becomes an anonymous block and no longer a PART.
This is a problem as the Bill of Materials is no longer picking up those items.
Also when these W shapes are PARTS or Blocks they can't be manipulated using their faces.0 -
I want to correct the copy statement I made. If you use the COPY command the PART remains a PART.
What I did was used a LISP routine to copy i.e. (vla-copy obj) and that made the anonymous blocks.0 -
Personally, I use the mechanical browser only to get the part into the drawing. At that point, it is a special sort of block. Then, I immediately explode it into a Solid, so that I can do things like drill holes in it. So, while I do a lot of work in 3D, I ignore the mechanical features of BricsCAD platinum, except as a parts library to start with.
I started on AutoCAD v10, back in the late 1980's. The basic manual was perhaps 1 1/2" thick, but well written compared to most modern manuals. The benefit of the book approach, is that I literally went through it cover-to-cover. Some parts, I would gloss over, but the process meant that I, at least, knew what was possible, and so would know to go back to that feature and re-read it if I though it might be helpful.
Yes, the video training, and searchable help files are a great, and very helpful, thing that has been added since the Acad v10 days. But in reality, most of the documentation for modern software, including BricsCAD, is not very well done (well at least up to my v14 of BricsCAD). People simply don't spend their money for software based on the user manual, so there is no incentive for vendors to invest in them.
With the demise of the well-written manual from a software vendor, 3rd party books have filled much of that need for the major software packages. I don't know if there is a particularly good book for BricsCAD. Perhaps someone else can provide a recommendation.
-Joe
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I've used ACAD starting in 2000, so I know all about 2D. Never used 3D in drawing houses. I used an add-on to draw wall door & windows but never needed 3D. I jumped to Chief Architect 2 years ago to further automate the design & plan development. Still using BricsCAD for the details etc.
Recently I have an opportunity to do some Steel Detailing in 2D which I find a nice break from the everyday drawing. Looking at the tutorials it appears as though PARTS & Assemblies would automate the Bill of materials & the section views needed on more complex projects. So I'm demoing a Platinum version, I currently use Pro. But I'm not seeing the payoff yet. I'm sure I can get up to speed in the 3D environment quick enough but the Parts thing is coming up short.
I really wanted the automated Bill of materials feature. It looking like you need a mechanical Add-On to make that happen.Thanks for your input.
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An automated BOM can simply be done with blocks that have attributes. There is nothing else truly needed. It is important, however, that you fully understand whatever process and program you use. Otherwise, you may think your BOM is complete, when in reality it is not.
The processes used in Mechanical to create a BOM is very different from using blocks with attributes. If you see a list of a mechanical object, nothing in the description will actually tell you anything. That information has to be extracted by a special utility. That is part of the reason I was not motivated to use Mechanical, even though I have Platinum.
-Joe
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Thanks for the words of wisdom Joe.
As a long time Lisper I can do my own BOM with blocks but was hoping that PARTs would do that for me.
Looks like parts are not ready yet for prime time but I'll keep digging for now.I assume you make all your solids into blocks once in their final form & add the BOM info.
It appears that using PARTS to create steel shapes is handy, then explode them to modify as needed.
If that is the method & way I decide to go then Platinum is not needed.
Do you find Constraints useful in your work?0 -
Another option is Xdata with solids but not as easy as blocks, but with a user interface in LISP that would be an option too.
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akendall1966 Thanks for your reply in the other thread.
It appears to me that a PART is nothing more than a Special Block with xData attached with information about the part.
Assemblies & Parts in separate drawing act like XRef's but are a special case used in the Mechanical environment.My current project is a Steel structure using vertical W-shape & round steel pipes as verticles and smaller W-shapes
as horizontal members. Mix in some angle iron for diagonal bracing and you have the skeleton. Later add handrails & walking surfaces.
Some shapes are welded & some have plates welded to the ends & then bolted to existing structures.As parts go the shapes (solids) are quite simple.
Say I have 20 of the main horizontal members & 2 or 3 need holes punched in them at differing locations.
I haven't figured out how to make 3 copies & save them as New Parts.Placing the parts, for me. is a multi-step process. 3D align the part at the desired face of another part & the change the Z to move to the final location.
I assume that is the normal procedure.In the tutorials, I watched they were able to select a face of each part & move the part into position. I have not been able to do this with the W-shape parts I created.
I'm hoping it will come together as I learn more about the 3D environment.
Thanks again for the feedback.
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@Charles Alan Butler said:
As a long time Lisper I can do my own BOM with blocks but was hoping that Parts would do that for me.First, I think you have been too humble in your messages. I realize now that you are a very experienced CAD user. I am sure the 3D skills will come very quickly for you. Your own insight will be valuable to me. So, please share them here, and describe your own final decision, and why you rejected other approaches.
Looks like parts are not ready yet for prime time but I'll keep digging for now.
Let me emphasize that my experience is only up to version 14. And in reality, I didn't devote much time to it. Some of that was just weakness in the tutorials and the manual, which frustrated me, but may have been significantly improved. So, it is quite possible that the current version, both the manuals and the features are developed enough to make a difference.
I assume you make all your solids into blocks once in their final form & add the BOM info.
In my case, I have been making the models for every production drawing into a block that I used as an X-ref. Many of them were assemblies and weldments, which had their own manually created BOM. It was just too much effort to try to make every piece a block. Part of that is that there was no way to make the length of a piece of metal show up in a property. Also, sometimes I did not use a solid, because a mesh has the ability to allow you to stretch multiple 3D objects. Though, anything with curved surfaces, or holes put into them, are not easy to do as a mesh. I called this "user parametrics" because the user has to know how everything will change length or shape when they use the stretch command. You have to be careful to avoid doing things like stretching a piece of pipe perpendicular to its axis, or you end up with a pipe that is distorted. Years ago I worked at a large theater and used AutoCAD LT, that does not have 3d capability. I used it to design the framework for large mobile set pieces. For the wood flooring and skin, I normally used old-fashioned 2D "solids" (when the work "solid" was used it originally referred to a 3 or 4 vertex area that was filled in with a solid color) However, one of the tricks to make the drawing in 3D, was to give the 2D Solid a thickness. It would extrude to be 3D, even if it was not a 3D solid as we think of it today. An advantage of this was that, if you stretched a piece of wood that was 1/2" thick, it always stayed 1/2" thick, and flat to the plane where it was created.
I share this to emphasize that there are generally many approaches to the way to do a drawing. Sometimes trying to encode everything in the CAD program starts to make things cumbersome. A lot depends on the end goal. Putting in all the constraints to make a model fully parametric takes a lot of time. Also, it can be difficult to predict how a model might be changed in the future, and thus, all your parametric effort may be in vain. If a sheet metal part later gets changed into a stamped piece, or one welded from flat sheets, all your constraints are useless.
It appears that using PARTS to create steel shapes is handy, then explode them to modify as needed.
If that is the method & way I decide to go then Platinum is not needed.In my case, I do feel that my upgrade to Platinum was unwarranted. Note that once upgrade, you generally have a higher upgrade cost every time you decide to go to a new revision level. So, the increased cost is not just a one-time fee. Though, in BricsCAD's favor, they don't have as much an ongoing increase in upgrade fees as some other CAD vendors.
Do you find Constraints useful in your work?
Very rarely do I find Constraints to be useful, and almost never use them. In past years I was close to being an expert with SolidWorks. There, of course, parametrics are pretty much demanded for everything. But, they also made them a lot easier to use. At least up to v14 of BricsCAD, they were just too cumbersome to use to any extent... at least for my personal situation. This can vary a lot among different users.
-Joe
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@Charles Alan Butler:
FYI: there are a couple of Lisp functions for dealing with mechanical components and sheet metal: bmlispget, smlispget and smlispset. These functions all have many features. See the 'BricsCAD SheetMetal LISP API' section in the LDSP Help file.0 -
Thanks Roy, I'll check it out.
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Hi, I dont really use any BOMs
for moving things around check my little video for beginners. One thing that is a bit confusing in the beginning is that if you are i a plan view you can see your items as a 2d drawing if you turn on "ignore entity snap elevation" view from the side and move around there.
https://drive.google.com/file/d/0B5ou0c4CSi7yN1hMSlNUWHZLT2c/view?usp=sharing0 -
Thanks Patrik,
No sound on the video?0 -
Nop no comments
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