Page Last Updated and Links Checked: 24 June 2003 Page Last Updated and Links Checked: 24 June 2003 Comments On 3D Techniques
Modelling a building or landscape is different to modelling a still machine or component part. For example an architect or landscape designer may be very concerned to ensure that the model looks like what the finished object will look like and has to convey the enviromental influences such as the sky, light and shadow, perhaps at different times of the day or in different seasons. Also an architect usually will not wish to model every subcomponent of a building and may choose to use image mapping (texture maps) to convey appearence of complex surfaces and will incorporate landscape objects such as trees, vehicles and people. Overall, architectural models tend to be surface representations using the AutoCAD face and mesh entities.
A mechanical component designer is usually not concerned about enviromental influences and tends to use a matte finish and a few distant lights with a minimum of shadow to aid visualisation. They tend to have the lights and shadow turn off in any closeups of complex components. Interestingly, two rendering schemes may be used; one with contrasting colors to help define the systems or subsystems and another to achieve a more realistic appearance for marketing purposes. An engineer modelling a machine or component will favour solid modelling in order to have access to mathmatically based engineering information such as interference fit, volume, mass, centroids and mass moments of inertia for example. Even in a large complex machine the designer is usually obliged to accurately model every single part for fear of missing some critical intereaction and many will do so down to the last bolt and fastener.
Despite what has just been said an architect may choose to solid model a building and an engineer may choose to face a mesh entity to create, say, a cast pump housing. At the end of the day a 3D model created by a practicioner of any disipline may well contain lines with thickness and elevation ("2½D") as well as faced mesh entities and solids.
Line Thickness And Elevation "2½D" (ie "3D" Prior To 3D)
Varying line thickness and elevation remains a useful option in vanilla AutoCad that can be used in conjunction with wire frame surfacing and solid modelling to produce 3D drawings. AutoCad LT does not have any true 3D capabilities so this "2½D" technique of varying line thickness and elevation is particularly useful. Many of the associated commands are used in 3D generally and I believe line thickness and elevation is where learning 3D should commence.
www.3d-cadcea.co.uk CADCEA Ltd - Fundamental 3D Tutorials (Highly recommended!)
Good hype-free (British) introduction to 3D drawing and the rationale for 3D. Read everything starting with About Us ..don't just click GO To Tutorials. The free (beginner's) tutorial they provide to evaluate their training course, takes about two hours to do but can be down loaded in html format if want to work using your browser off-line.
The tutorial is command line based (only way you can get through extensive instruction) and fine with older versions of AutoCad and AutoCad LT. With A2000+ you have to use use -VIEW instead of VIEW but that is AutoCad's fault .. altering the way things have been done for years.
Try setting the browser on the left of the screen and put AutoCad on the right using the Windows Tiling button (the button in the center of the group of three in the top right hand corner of the screen). A big screen is required, or you can refer to them one at a time from the Windows System Tray.
cadcea3Dlinetutorials/tasks_myformat.html A summary.
www.echomags.com.au/help/autojul1.htm ## Does not come up. See local file underneath ##
Tutorial 1 of a line thickness, elevation and height based "3D" tutorial by Basil Harvey that can be done in Autocad since Rel 2.18 (with advanced drawing extension) in 1987 long before 3D was introduced and is all that's available to AutoCad LT users today. Appeared July 1997 in Multicad Magazine www.echomags.com.au. ## Does not come up. See local file underneath ##
linewidthkitchen/autojul1.html A summary.
Modelling Using Faced Mesh Entities
www.bath.ac.uk/~abshhkc/lectures/acad/index.html University of Bath R2000i (3D)
www.bath.ac.uk/~abshhkc/tutorials/index.html ## 400 Not Found 9Dec02 to 24June03 ## An alternative index that lists a number of tutorials including 3D Studio Viz.
Henry Chow's Bath University URL rererred to in the 2D section re-listed here for completeness. Framed site so just refer to the left hand frame menu for the 3D items (ie Chapters 7, 8, 9 and 10).
Look under Resources for Tutorial drawing files (2D and 3D) you need (468kB zipped unzipping to 1234kB) and the PDF (3.8Mb/4.6Mb) files with instructions and images of completed work. With Winzip 7 I am able just to open the files I want use it without having to unzip everthing.
pisces.sbu.ac.uk/BE/SUDP/Architecture/BA/IT/L2.html South Bank University -London (3D) ## not responding -can't resolve 21Sep02 to 24June03 (see also acad2Dtuts ##
Good 3D AutoCad (and 3D Studio) tutorials and tests. Old (R12), but the the keyboard commands and the concepts detailed are core AutoCad skills that are very well presented. Links have appeared to go down on this site in the past so I have saved the 3D AutoCad tutorials here at:-
sbututs/courses/L2.html Index for 3D Tutorials, Lesson 10, Lesson 11 and Lesson 12.
sbututs/courses/acad3d/l10_myformat.html My Summary of the first of the 3D Tutorials (Lesson 10) with some provision for problems that arise for A2000/i/02 users.
we-r-here.com/cad/index.htm The CAD Guy. 3D (and other) tutorials. Some Autolisp.
Click on 'Online Lessons'. Scroll down to 'Introduction to 3D'. Note the many other non-3D tutorials.
Note he includes 2D Isometic drawing with 3D. He uses Word 97.
See also 'Programs' which has some well documented Autolisp files. In particular I downloaded IDDIM.LSP (1k) which will create a leader pointing to a picked point and list it's x,y co-ords. Can be found from Autolisp section of the Customising page. Compare it with Ralph Grabowski's similar program.
www.3dcafe.com/asp/tutacad.asp The 3D Cafe.
Good tutorial site. 3D emphasis but other tutorials and topics too, eg Rhino3D. Useful for those people starting in Cad, graphics, design or web development.
www.arch.usyd.edu.au/~paul/courses/dc-c/intro_acad/3Dintro.html Paul -Sydney Uni. School of Archit.
Introduction to 3D Concepts, Documentate then complete the drawing of a 3D Temple. Good. Uses R14.
www.arch.usyd.edu.au/~paul/hy/4hy/auto/index.html Paul -Sydney Uni. School of Arch.
An overview of AutoCad2000 and 3D methods that could be usefully summarised.
Headings would be: Background, Objects, View, Render, PSpace, Printing,Cad to Web (Acad to dwf, Acad to VRML only), VRML.
www.haaug.com/downloads/blocks.htm Houston Area AUG's download page. ## 21Sep02 to 25Apr03 and before problems with this once good site. Maybe shut down ##
For symbols and drawings. Trees (plan and elev), shrubs and other landscape objects such as cars, trucks and people. Listed here for the three canoe entries.
Solid Modelling (Note US Spelling: "Modeling")
www.fbe.unsw.edu.au/Learning/autocad/R13/3D
Uni of New South Wales Faculty of the Built Enviroment R13 3D Solids Tutorial listing. In Tutorial 1 and 2 you are introduced to the Solid Primatives. In Tutorial 3 you make two rooms with walls, doors and windows and put in some furniture you can download. In Tutorial 3a you are shown how to make the furniture. In Tutorial 4 you make an animated walk through. Done in R13 but it's core AutoCad learning.
(AJ Note: See CreatingSpaces folder. Possible Solids Listing)
createspace/solids1.html My Summary: Tutorial 1 -Intro To Solid Primatives.
homepage.dtn.ntl.com/terry.rawkins Terry Rawkins of Bracknell and Wokingham College. 3D listing.
Good (2D and) 3D Tutorials by Terry. See the stratagies and safetynets used with 3D drawings.
Click on Revision Questions which includes 3D and Solid Modelling section.
resources/myresources.html#3dforkextrude
A good 3d extrusion presentation (with some other .scr and site listings) I found at the Peninsula AutoCad Users Group members.tripod.com/seva-aug.
www.digitalcad.com/Htm/tutorials/opencad/solidparts/solidpartspt1.htm
Create standard views of solid parts and assemblies. Uses A2000. A project based tutorial where you place orthogonal and sectional views of solid assemblies on drawing sheets using the SOLVIEW and SOLDRAW commands. Tools used allow documenting parts created with AutoCad's solid modelling commands.
www.teknigroup.com/acad/tutorials/core_s.htm
Obtaining ACIS Solids from existing 2D Drawing Views
A short tutorial on creating acis solids from existing 3 view 2D drawings.
2d_to_acis_solid_conversion/core_s.html ***Not Found 2/5/02 My attempt at a local copy but the drawing file download came up Not Found. So I either make a drawing to apply the instruction to or remove the entire entry. Or hassle the webmaster over the link ..who knows it might come good itself.
Shading
Careful selection of color used when drawing lines with thickness, extuding or using primatives to make solids or surfacing a mesh entity, can, with one or two lights, result in a very pleasing and effective 3D model that is sufficient for the purpose and keeps costs at a minimum. With the solid model component fine fillets on otherwise square edges or chamfers on parallel straight edges can help provide contrasting light reflection and improve appearance.
Use the appropriate tool depending if the model is predominantly flat or has rounded surfaces and consider using the 3DORBIT tool to revolve the model slightly so the default light works to maximum effect.
Materials And Rendering
If you are disiplined, a lot can be achieved in a small amount of time with some materials and lights. You can always get a better visual effect if you do some more work on the model so decide in advance when to stop and stop. If you need a super good cosmetic appearance, give it to an expert, pay the fee when it comes in and in the meanwhile get back to productive work yourself.
An issue for me is everyone saying AutoCad's rendering and lights are very basic and I should go out and buy Autodesks Studio Viz (ex 3D Studio). Well I won't. I can't detect signifigant modelling improvements since R12. Considering the improvements to other parts of AutoCad, the failure to make even token improvements in model editing or rendering indicates, in my humble opinion, a deliberate policy of crippling AutoCads capability to generate sales of other products. AutoDesk share prices are the highest they have ever been and they have the highest share of the market they have ever had, so as a matter of principle (and the fact I can't afford to buy their other products) I stick with vanilla AutoCad and if I need more, I use products from 3rd party suppliers that work well with AutoCad (see the 3rd Party 3D Modelling Aids section).
www.cadinfo.net/editorial/render1.htm Brief Lesson In Rendering -CadInfo Net.
rendering/render1.htm My Summary
www.triton.cc.il.us/faculty/fheitzman/render.html Render and Light tutorial. Straight AutoCad example and then using AccuRender.
rendering/triton_render.html My summary.
Note: The straight AutoCad component deals with, or at least mentions texture, materials, mapping, spot lighting, distant lighting (sun) time/location, rendering, making a Scene and making Mslides. The quickly drawn 3D model is a simple "virtual world" consisting of a flat plane made using a long wide thin BOX with a SPHERE and a CONE placed on it. The tut is excellent but it is not really about modelling. It is about lighting, materials, rendering and making scenes and slides of an existing model.
www.cadtutor.net/acad/acad2ki/sun/sun.html CADTutor's sun light tutorial (main listing in 2D section).
www.cadtutor.net/acad/acad2ki/sun/shadow.html CADTutor's shadow tutorial.
3rd Party 3D Modelling Aids
While some competitor products might do some things better, one stength of "vanilla" AutoCad is you can do anything with it and some 3rd party products help considerably. Here are some products for use in 3D work I hold in high regard.
Notes: AME stands for Advanced Modeling Extension. It was an optional, but fully integrated modelling tool available with R11 in 1991. Release 12 had an optional Solid Modeler, the Advanced Modeling Extension, Release 2.1. This had a wider range of solid modelling tools. R13? No change between R14 and 2000/i/02. (Product/development crippled by marketers to promote sales MDT, ADT, Inventer, 3D Studio MAX/Studio Viz ??).
www.black-cad.de
Unfolding a surface model transition piece made with RULESURF or intersecting pieces plus PEDIT3D and moving drawings. Free demonstration download.
AutoSolids -3D Modeling Enhancer For AutoCad
www.autosolids.com For AutoSolids A2K, 2K Express or DEMO.
An AutoCAD add-in that extends the 3D capabilities of AutoCAD, by enhancing the solid modelling capabilities of AutoCAD and the coordinate system (UCS), Viewing, and Visualization commands. I downloaded a copy of the manual in pdf format and the free AutoSolids A2K DEMO (which has a reduced set of features).
Cadalyst Sep 2001 AutoSolid A2k ver 2.0.3 article Has useful content but sounds like it was drafted from press statements and looking at the screen on startup. Don't get feeling he produced a drawing with it.
Cadense Aug 2000 AutoSolid ver 1.0 article Practioner and Author John E Wilson states; "Like AutoCAD, AutoSolids is command driven, and you can initiate its operations from the command line, toolbars and menus. You can conveniently divide the AutoSolids commands and features into four categories: (1) coordinate-system management, (2) viewing enhancements, (3) solid-model construction and (4) solid-model editing". He then expands on each catagory pointing out the main reason for using AutoSolids will likely be its ability to edit solid models. You edit them by editing their primitives. After selecting the solid you want to edit, all of its primitives are displayed, and you can edit each of them individually. Good article (I bought his book: 3D Modeling in AutoCad).
CadInfo AutoSolid ver 1.1 article. Experienced user. John McIver deals with some aspects not covered by John Wilson in the Cadense article above including format compatability, using QuickDraw facility to lay out 2D views and is blunt about why he uses an AutoCad "plug-in" to give a near professional parametic facility instead of converting to a separate solid modelling program. He concludes by stating: "I have over 15 years of experience in using AutoCAD and know the program very well. While I have no doubt there are better CAD programs around, to sacrifice that depth of knowledge to move to another program is a very major step, and not one I'd want to make without good reason. AutoSolids provides me with the tools to perform sophisticated solid modelling, while allowing me to remain within my familiar environment, and so protect my AutoCAD knowledge base. This, to my mind, is the single most attractive feature of AutoSolids".
AccuRender -Rendering For AutoCad Avoiding Need For Studio ViZ/ 3D Studio Max
www.accurender.com McNeel's AccuRender for A2000+
For AccuRender to use instead of AutoCad's rendering facility to create stunning life like images using raytracing and radiosity. Makes photorealistic, still, panorama, and animation image files from 3D models inside AutoCAD. From McNeel, and like his Flamingo Rendered for Rhino3D, you can download a 7Meg zipped Demo version that has no time limit. It has a reduced selection of textures puts some thin grey lines across the render (same demo deal as McNeel's Flamingo Renderer for his Rhino 3D.) Educational US$195 Labkit US$975 (Apr 2002).
www.accustudio.com AccuStudio site. Supports AutoCad and Rhino
An AccuRender user sponsored web site with news, tutorials, support, materials, objects, plants, lights, backdrops, and events.
Saw tutorial on how to make animation from AutoCad using Accurender!
www.spaug.org/Rendering_Index.Html#Useful South Plains AUG. 5 out of 5. Useful Accurender 3 tips and information. I saw lisps to help do animation. Page updated 15 Apr 02.
Rhino3D -Free Form Modelling And Format Conversion
Rhinoceros 3D fills in the cracks and the chinks left when using AutoCad. The 24 file formats it opens and will Export Selected to means it is worthwhile having one seat even evem if you do not need to draw organic shapes to bring into AutoCad.
www.rhino3d.com For Rhino 3D, a NURBS modeler. Uninhibited free form modelling of any shape you can imagine with the accuracy needed to design, prototype, engineer, analyze, and manufacture anything from an airplane to jewelry.
The odd thing is that the feature that proved to be useful to most users is Rhino’s ability to translate between 3D file formats. Rhino can import and export IGES, ACIS, Parasolid, STEP DWG, STL, 3DS amongst others. It will also convert NURBS surfaces to meshes which is useful for machine shops and rapid prototype services.
www.rhino3d.com/support.htm For Links to newsgroups and support.
www.rhino3d.com/tutorials.htm Links to tutorial sites. Good. Starts with commercial offerings then plenty of sites of committed users offering tutorials.
www.flamingo3d.com For Flamingo3D.
This Rhino plug-in brings AccuRender's raytrace and radiosity rendering technology to Rhino.
Education price US$195 Rhino only US$295 Rhino and Flamingo option
Evaluation version of Rhinos and Flamingo have less materials and thin lines across the rendered image.
AccuRender material and plant libraries also work in Flamingo.
www.cadserver.co.uk Rhino 3D (and Flamingo) article in Feb 2002 CadServer.
Article refers to McNeel, AutoCad, AccuRender and Flamingo relationships.
Nurbs is defined. Large number of formats supported (incl A2000 dwg/dxf) fully listed. Mentions popular as tool to convert between formats.
Rhino 3D is economical and powerful and should interest anyone choosing to stay with vanilla AutoCad but would like an unlimited freeform 3D capability.
www.mcneel.com McNeel and Associates
The biggest AutoCad dealer in the world and Tom McNeel is the man behind Accurender, Rhino 3D, and Flamingo (brings AccuRender's raytrace and radiosity rendering technology to Rhino 3D). Support and forums for these various products. See also EasySurf and EasySite (built on EasySurf), AutoCad add-ons for ground modelling.
rhino/myrhinonotes.html My Rhino Notes.
www.amazing3d.com/services/tutrhino.html The Rhino Tutorial listing that the Mushroom and Face tutorials above were found in.
rhino/toilet/toilet.html My toilet bowl (two objects). (Uses what I've learnt in the Face and Mushroom tutorials in the Rhino 3D page ..this is the Rhino 3D section of AutoCad 3D Page which treats Rhino as a 3rd party aid). Also a translation exersize. Besides a jpg you can view there is the Rhino ver2 3dm(126kB) file I made plus the various formats I chose to Export to, namely 3D Studio Max 3ds(125kB), AutoCad2000 dxf(413kB), AutoCad2000 dwg(114kB) all in individual zip files.
What I was able to do with the various formats created from the Rhino file:-
The 3ds was brought into AutoCad2000 by Insert>3D Studio and was a polyface mesh. This was done in the Object layer and it created three layers namely ASHADE, OBJ_1 and OBJ_2 (an object was on each OBJ layer).
The dwg was brought into A2000 by File>Open. It created it's own DEFAULT (the objects were in the Rhino Default layer) layer containing the two objects and was a polyface mesh.
The dxf was brought into A2000 by File>Open. It created it's own DEFAULT layer containing the two objects and was a polyface mesh (identical to dwg).
Note: There were 24 formats under File>Save As, or the same 24 formats could be File>Export Selected to. Also of interest (to me) are IGES (has Inventor 5 option) and ACIS.
IGES and NURBS Surfaces in AutoCAD
NURBS splines are standard object types in R2000+/R14/R13. Some confusion arises as to the nature of splines and surfaces. AutoCAD does not support NURBS surfaces, nor will IGES translate NURBS surfaces into AutoCAD without conversion. NURBS surfaces will be translated as either Polyface meshes or NURBS spline wireframes. There will be a great deal of accuracy lost in a model is NURBS surfaces or splines are converted into polylines or polyface meshes. Mechanical Desktop will accomplish the translations accurately, but standard AutoCAD will not.
Tips, Hints And Reminders
The well known flattening method:
_move;_all;;0,0,0;0,0,1e99;_move;_p;;0,0,0;0,0,-1e99;
is now advised by Autodesk's Tech Support as a possible solution to remove Z components from coordinates in a drawing in TS44903
Contact: Aussie John wpsmoke@yahoo.co.uk