Jump to content
Wilbri

Assistance with 3D drafting

Recommended Posts

Wilbri

I hope that I am in the right area as the initial questions more likely belong to the Beginners area.

In order to get us under way, I believe that some short background history is important.

I commenced my career spending 4 years obtaining some basic practical experience as an apprentice Fitter and Turner, as was the norm for anyone wishing to persue their interest in drafting or other mechanical engineering office activities in those days.

This was in the Iron and Steel industry. On completion of my apprenticeship I was assigned as junior darfsman (2 years) in the company's design and development office and after having spent 5 years moved to the city of Johannesburg working as a draftsman any eventully design draftsman, DO manager eventually as Design engineer, Engineering manager and construction site manager for a few companies prior to having to go into retirement due to a dehabilitating ailiment (periphoral neuropathy). I relocated to Durban some 28 years ago.

Fortunately my last company has retained may services as technical adviser on a Bulk storage tank maintenance contract with a large oil refinery.

I now work from my home office preparing, method statements, drawings and planning schedules for them, using their PC which fortunately is equipped with AutoCad 2007.

I have not received any formal training in AutoCad (Self taught and using many bad practices which are difficult to break)

I consider myself pretty adept at 2d drafting although I continue to learn something new almost every time I go onto CADTutor.

Yes paper space utilization neededs to be mastered, but what I realy wish to do is become proficient using 3D as I am well aware of the benefit.

 

So having said all this let me begin with my first question:

 

Please advise me how you proceed to set up a drawing for 3D drafting purposes?

I have drawn in 3D but would prefer to do things the right correct way at this stage.

I look forward to receiving your replies.

Share this post


Link to post
Share on other sites
ReMark

I see you have gotten the ball rolling Wilbri. Good for you.

 

When you say you "have drawn in 3D" what exactly does that mean? Have you used any of the following commands or features:

 

-Extrude

-Regions

-Subtract

-Union

-Interfere

-Move, copy, rotate faces

-Flatshot

-SolProf

-SolView/SolDraw

-Sectionplane

-Visual styles

-Sweep

 

Have you a fair understanding of how to orient the UCS to be able to draw on a particular plane?

 

I'm assuming any 3D work you do you would be creating solids as opposed to surfaces correct?

 

And you're becoming more familiar with the use of viewports in a layout as well?

Share this post


Link to post
Share on other sites
SuperCAD

My first tip would be that if you are serious about doing 3D modeling (different from drafting) then AutoCAD is not your best option. Look into either Inventor or SolidWorks for 3D modeling. AutoCAD is not set up to carry a change from the 3D model through the 2D drawings that were generated from it, whereas Inventor and SolidWorks WILL update all of the details when the model is altered.

 

That said, you can still use AutoCAD to model a 3D object and create the 2D geometry (i.e. Details, Elevations, Sections, etc), just be prepared for the headaches that come with it. And I speak from experience because this is how we do our drafting/modeling where I work (we will be moving to SolidWorks by years end).

Share this post


Link to post
Share on other sites
ReMark

Given Wilbri's circumstances I doubt very much whether he or the company he works for will be switching programs. It's up to us to help Wilbri be as efficient/productive as we can given the limitations that he is working under. Note that he is using a PC provided by the company and an older version of AutoCAD that I doubt they will be upgrading.

Share this post


Link to post
Share on other sites
marmo

A quick example of design in autocad 2d/3d:

 

You can use "section plane" to view a live-section and generate the corresponding blocks. The blocks, that are designed only with lines and hatch, can be updated at any time.

Than you can frame different views, and blocks in paper space.

 

_001.jpg

_002.jpg

_003.jpg

_004.jpg

 

It 's true that unlike other software autocad has its limits...

Share this post


Link to post
Share on other sites
marmo

Autocad "like 3dMax"... a little strategy :P

 

Autocad is not a parametric software.

I can say it better: autocad is almost/parametric .

 

For example:

A circle i a parametric shape (rectangle not), if you have enabled properties panel you can change radius/diameter at any time.

 

_001.jpg

 

A cylinder is parametric solid only for it's height, but is not parametric his radius or diameter.

 

_002.jpg

 

If you make a block and duplicate it you have many parametric solids, because you can change it's size along 3 axes independently.

 

_004.jpg

_005.jpg

_006.jpg

 

Then you can select and reselect it with "quick/select", you can update and explode, for other modify.

However, if the block is made with complex and curved surfaces, it can not be exploded.

_003.jpg

Share this post


Link to post
Share on other sites
SuperCAD

Point taken, ReMark, but again if he is serious about doing 3D modeling he's going to want to strongly suggest that his company move to a different software. We struggle with the limitations of AutoCAD and 3D modeling everyday, and these limitations have cost my company thousands of dollars.

 

One of the functions you should learn to use right away is PressPull. It makes creating 3D objects much simpler than having to close a polyline and extruding it. With PressPull, the shape doesn't need to be closed and the endpoints of the lines can even overlap and extend beyond the boundary of the shape you want to create. Another benefit of using PressPull is the ability to create a solid from a shape made with spilnes (since you can't use splines to create a close polyline, unless you flatten it and change it to a million polylines, which gives you way too many faceted edges). One thing to remember about PressPull though is how to enter your values. A positive value will always pull the shape towards you, and a negative value will press the shape away from you.

 

Also from my experience, do NOT dimension a 3D solid in a viewport. AutoCAD does not know how to handle dimensioning a solid object, and the dimensions will go all crazy on you. Make your sections and elevations using the section plane and dimension the 2D geometry that is created that way.

Share this post


Link to post
Share on other sites
Wilbri

Remark and SuperCAD many thanks for your input which I was busy replying to when I needed to stop due to having to leave to visit friends friends and have just returned home. Since that time further comments have beenreceived including Marmo.

 

First of all ReMark.

In reply to your first submission, NO cannot say I am familiar with most of the terms you have noted other than extrude.

I did attempt some 3D solids drawing back in 2004 when I had access client software and did attempt doing some excercises from George Omara's book Mastering Autocad, so have an idea of solids. (I must admit in being impressed at the time but was mainly occupied in producing 2D arrangement and shop fabrication details which I continue to do at present.

I was not actually anticipating going directly onto 3D solids, but rather 3D surface drawing, somthing similar to the 3D drawing you sent me earlier in the year.

Which ever way, I would like to be able to produce a 3d drawing for two specific reasons: The first being that most of the younger engineering graduates seem to be at loss when reading a 2D drawing, as the have possibly gone straight onto 3D, also 3D is a very useful means of presenting a picture to a client with no engineering background.

And secondly in understanding 3D surface drawings as I do I can achieve producing 1 drawing in 3d and then am able to display the outer plan and elevations in separate viewports for manufacturing purposes without haveing to draw them separatly as I do in 2D namelt Plan and Elevations.

So this is basically where I wish to start unless you consider it advisible to skip this and go staight onto 3D solids

This is possibly not what I had.

I am familiar with the 3D UCS planes.

Yes i am reasonably comfortable in terms of understanding viewports but still need to put this into practice which I have not managed to do yet.

 

SuperCAD.

Yes I am aware and very impressed with 3D parametric modeling software as offered by Solid Works and Alibre although I have not seenbeen exposed to Inventor assume it to be along the same lines. However the cost of this software is prohibitively expensive in South Africa, and due to the very low demand for work of a general mechanical nature would certainly not yeild any return on an investment of this magnitude.

The Acad 2007 facility offered by my client serves its purpose that of producing drawing arrangement and fabrication drawings for the repair of bulk storage tanks, namely platework, angle rings nozzles and odd support brackets which works very well using the existing software.

So at this time I will stay with Acad 2007.

 

Marmo

Thank you for your contribution.

I have not had time to study the content yet, but looks like the type of drawing I was expecting to progress to.

 

I look forward to your receiving your replies.

Edited by Wilbri
Grammatical correction

Share this post


Link to post
Share on other sites
JD Mather
I was not actually anticipating going directly onto 3D solids, but rather 3D surface drawing, .....unless you consider it advisible to skip this and go staight onto 3D solids ......

 

Forget the old surface commands (unless you jump to 2011).

You might go through the tutorials in my signature.

Share this post


Link to post
Share on other sites
Wilbri

Marmo

I have now had a chance to review your material and confirm that I follow the concepts and respect to your efforts to offer assistance.

Unfortunately I believe this information to be beyond my present understanding and capabilities.

I have come out of 2D and also understand how to draw simple isometrics but need to start at the begining if 3D by being introduced to initial set-up and correct practices of drawing in 3D, so as not to adopt the same bad habits I previously got into be attempting to teach myself 2D drawing, as it has taken a long time to change these habits and do things correctly.

 

I hope that you understand my situation.

Share this post


Link to post
Share on other sites
marmo

Ok wilbri,:)

Now the situation is clearer.

I think the best thing to start is to get to know commands about 3d and especially how to move with the coordinates ucs, with the "old" system of the UCS command and with the new system of gizmo ( commands 3dmove, 3D rotate).

The 3d autocad always starts with a good 2d,wich you already know! So you're halfway there!

I am at your disposal for any advice, if I am always enlarge to provide!

Regards:)

Marco

Share this post


Link to post
Share on other sites
Wilbri

Thank you Marmo

I look forward to your comments as we progress on this (to me) new venture.

Prior to leaving Johannesburg 28 years ago I had many close Italian friends and unfurtunately have not up to now been able to visit your country.

Had an older South African friend (since deceased) who lived and worked in Milalo forn 25 years before returning to SA who paintted a very vivid picture of your area to my wife and I.

 

Enough of this sentimental story, let us get down to business.

So folks with I would imagine by now, (which I realise that Remark has, as we corresponded earlier this year), where do we begin?

I look forward to the challenge of becoming a competant 3D user.

 

Being of senior age I would like the opportunity of providing the following comment.

You will notice that I never use the term "CAD operator", as we have many of these in our country. To my mind the term refers to someone who can portray what I call a "pretty picture" of an object but unfortunatly has no no understanding of the concept when it comes to having to produce/manufacture whatever they have drawn. And to add to this they are called "designers"???

Come on, this is Engineering and not Art, and I say this with great respect to may people who have of both gifts.

Share this post


Link to post
Share on other sites
ReMark

My suggestion would be for one of us to provide you with a drawing of something rather simple and let you have a go at reproducing it in 3D. Maybe we can suggest some of the commands that would be required to achieve the goal. We've got to keep in mind that you still have to earn a living.

Share this post


Link to post
Share on other sites
Wilbri

Thank you Remark

 

I approve of your suggestion.

I would then have something tangable to work with the benefit of calling for help when needs be and receiving correction when I have strayed.

 

As regards earning a living, other than requestst from my major client possibly every 6 to 9 weeks and usually only takeing 2 to 3 days work, there is not much about at the moment and and when I do receive an assignment I end up having to negotiate a reasonalble price and on completion struggle to get payment for for the agreed services. So I am hoping that athe 3D approach will help me to improve this situation.

All large projects over the past 5 years are linked to infrastructural development so are mainly aimed at the civel and structural engineering disciplines.

Share this post


Link to post
Share on other sites
ReMark

Infrastructure you say? That's interesting. Maybe we can incorporate a 3D design of a simple equipment hoist assembled from some structural steel shapes and incorporating baseplates, piers, and a chain driven hoist running along a single beam. How does that sound?

Share this post


Link to post
Share on other sites
ReMark

An example of a possible assignment.

 

Adjustable Guide - Assignment 1.dwg

 

The attached file has been saved in 2004 file format.

 

The views in the layout were created using the combination commands of SolView & SolDraw. If you look at the model space objects you'll not only see the original object but the flat views AutoCAD created using SolView that are displayed in the layout. Looks a bit strange doesn't it?

Share this post


Link to post
Share on other sites
Wilbri

That sounds very interesting.

Something that can be locally produced ans offer a relatively cheap method of moving materials without needing to pay expensive rates for the hire of a mobli crane or occupy valuable tower crane time.

is this what you are getting at?

I have always been interested in designing and detailing chemical and mechanical plant and equipment, so let us go for it.

Years ago I had a short stint at selling primarally, locally manufactured stone crushers and ancilliary equipment but also had imported portable concrete batch mixing plants and asphalt plants as part of my itinary.

These 2 plants are very much part of infrastructural development but definatly too sophisticated to start off with.

Share this post


Link to post
Share on other sites
Wilbri

Sorry my previous reply was generated prior to receiving your adjustable guide drawing.

Yes I cant say that I have come across this type of model space view before.

Referring to Orama's book on AutoCad 2004 he does not mention or use this terminology,

Share this post


Link to post
Share on other sites
ReMark

The hoist I have in mind would be used to move small pieces of equipment into a decontamination tank for cleaning. Imagine two frames (each like an upside down letter "U") supporting one long bean on which is mounted the actually chain-driven hoist (2 tonne). A fairly simple arrangement probably requiring four columns each with two connecting beams and the main hoist beam bolted to the frames as assembly has to be put in place a section at a time. Each column would require a baseplate and all four columns would be mounted on 6" high concrete piers with two inches of high-strength grout between the top of the pier and the bottom of the baseplate.

 

Do you want to try to draw the adjustable guide in 3D? Since you have a drawing the proper dimensions on it already and an actual 3D model too you'd actually be a little ahead of the game so to speak. When I got this as an assignment all I had was a hand sketch of the top, front and side of the guide with dimensions on it; no isometric view or 3D model was included!

Share this post


Link to post
Share on other sites
rvpas

Hello Wilbri,

You have 2 manners to start the 3d

The first one is by starting of a material raw and to model it either, in the case of existing 2d plan to reconstruct the 3d above.

I reassure you, you is not the only one to make of the 3d from autocad and since the DOS versions, there were constant improvements.

Certainly, it is certain that there are CAD tools or BIM better adapted.

But I train many trainees in your case and they manage to make models 3d impressionants.

As indicated it Marmo, you can use section plane to export them in another drawing to complete it for example.

Only defect, as said it supercad it is in case of modifications and there we regret having no parametrics tools as inventor, solidword or other.

But with a little of time, we manage it...

Some advices :

- create layers dedicated for every objects

- use the viewports in the model space

- use the ucs face, 3points, UCS dyn

- create 3d blocks of repetitive objects like in 2d

- use Xrefs for complex assemblies

- create intermediate copies during the process of modeling

- use regions for certain profiles

Include a small tutorial to start your first mass modeling

Tutorial : http://www.4shared.com/document/jUNb1xH3/Modlisation_dans_la_masse-_Mas.html

model finished : http://www.4shared.com/photo/B2M0PhU0/platine.html

and example from 2d : http://www.4shared.com/photo/VY4W_ln6/3d-etrier_galet.html

to ending some examples

pompe doseuse.jpg

coupe cuve beton.jpg

détail platine2.jpg

Good luck

Pascal

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...