Any tips on general good practice when 3D modeling?

[Posho91]

Hi folks.

 

So i've recently completed my first building design as a 2D drawing package and a 3D model in autocad, so that I am able to create rendered perspectives and internal views to a good enough standard to present to my tutors after the xmas break...it has been a tough 2 week learning experience!

 

But I'd like some advice on general techniques/ workflow/ good practice.

For instance, at the end of my project my layers were a mess, the solids of my rooms were all unioned leaving me for some reason unable to texture individual faces. I could make images to a certain standard, but in general it was messy, complicated and time consuming Etc....well...i'll just try and figure out a few questions...

 

-When you move from 2d to 3d, should you start a new file?

-How do you choose how to separate layers, do you do it by material, object or plan ahead to imagine which bits will need different textures etc.?

-After unioning the wall objects together for each 'building' why was I unable to select individual faces for texturing, only the whole solid at once?

-Which objects should you xref and which is there no need to?

-What is the best way of creating the ground solid, extruding down?

-What is the best way of then creating a separately selectable floor object for the inside of the building?

-Where do you store your files? is it any quicker to store them in the autocad folder?

 

-In general what is the order you do things when you make a 3d building model? (I pretty much based everything off this, which is basic: http://www.cadtutor.net/forum/showthread.php?10523-How-to-3D-Model-a-2D-Floorplan)

 

I'll add some more when i remember them.

Thanks if you can help!

[SuperCAD]

 

 

1. When you move from 2d to 3d, should you start a new file?
   
2. How do you choose how to separate layers, do you do it by material, object or plan ahead to imagine which bits will need different textures etc.?
   
3. After unioning the wall objects together for each 'building' why was I unable to select individual faces for texturing, only the whole solid at once?
   
4. Which objects should you xref and which is there no need to?
   
5. What is the best way of creating the ground solid, extruding down?
   
6. What is the best way of then creating a separately selectable floor object for the inside of the building?
   
7. Where do you store your files? is it any quicker to store them in the autocad folder?
   

1. I create a 3D model in one drawing, and then XREF it into my working drawing. I can still get all of my sections and elevations from the XREF, but it significantly reduces my file size of the working drawing.
   
2. If I were doing a house drawing, I'd separate the layers by floors (i.e. foundation, 1st floor, 2nd floor, etc.) then I would further subdivide by what I was trying to show on that layer (i.e. joist layout, electrical plan, plumbing plan, etc.). If I were drawing parts for manufacturing, I would separate the layers based on what makes sense for the part. For example, if it were one part made out of one kind of material, I wouldn't need a lot of layers. If I was doing an assembly of parts, I'd have to make a layer that was part specific so I could turn the parts on or off as needed.
   
3. When you union multiple parts, they become one part. In order to select only one face of the part, I think you need to hold down the shift or CTRL key (can't remember which one it is), then click on the face that you want to edit.
   
4. Any time you use a feature in multiple drawings, you should use an XREF. An example would be a floor plan that is used in many different sheets, assuming that your using one drawing file for each sheet. The floor plan would be XREFd into the lighting plan, the reflected ceiling plan, the joist plan for the floor above it, and so on. This way, if you needed to change the floor plan, it would update in all of the other drawing files when you opened them again.
   
5. Yea, that works.
   
6. Not sure what you're getting at, but I would create a separate object for each part in my assembly. If I had a cabinet that required 31 parts to be produces, then there would be 31 solid parts in my assembly.
   
7. Here at work all of our files are stored on a sever. This way, our computers aren't bogged down with the files and anyone can access them.
   

Hope that helps a little. One thing I would consider is the type of software you're using. If you're primarily drawing houses or buildings, you may be better served by using AutoDesk Architecture, ArchiCAD or any one of a number of programs that are better suited to the architectural world. Vanilla AutoCAD is a beast to use for drawing buildings that are prone to changes. It can be done with ACAD but a parametric program would be a better choice.

[Posho91]

Thanks, that's v. helpful.

 

1.Oh ok. So if i'm understanding you correctly... you basically work from a 2d plan, with lineweights etc. as it would be ready for plotting, then copy the plans to a new drawing for 3d, then extrude up etc., then xref back into the original drawing to produce sections etc. (On a side note, is that the norm or do some people create a 3d model first, then cut through and export their plan from that?)

 

3. Yeah I used right click, then subobject selection filter> select face, and tried to select the walls but it didnt want to do it at all...as if it didnt realise they were faces. Kinda odd.

I assume that selecting faces is the normal way that you'd render the outer face brick and the inner face paint for instance?

 

4. Ok that's handy for the future, at the moment i'm only really working with design drawings with the occasional structural drawing for 2nd year architecture at uni, so on the whole all i need is plans, sections, elevations, perspectives and 3d internal views just to represent the design, not any plumbing, services etc.

 

5/6. Yeah, I didnt explain too well, but basically, say you extruded a large area of ground down as 'soil/concrete' but then you want to have different flooring effects such as wood planks or carpet in different areas. If i were to select the current 'ground' that the walls were resting on in the model, it would select the whole thing...what do you normally do to render the interior portions of the ground solid different to the outside? I suppose I could plan ahead and extrude a 1mm thick floor inside each room ahead of rendering. what do you do?

 

I think perhaps for this project Autocad has been good as an intro into how this type of software generally works. I have the student version of Revit Architecture but I found it a bit overwhelming with all the different types of materials/ walls etc. since all I really wanted was to extrude upwards from my original floor plan. Hopefully i'll get a chance to play around with all three next term. Which do you prefer? We're also being showed microstation...which so far just feels like a less user friendly version of Autocad!

 

Ta.

[Cadderpillar]

1. I do as much as I can in 2d before I extrude up. I get everything all ready before I mess around with 3d.

 

5/6. I render each of the objects in the room a separate object. It is separate in the fact that it is different. If you need to be able to select something then make it a separate object.

 

_______________________

I design commercial playground equipment with CAD.

Edited January 7, 2011 by Cadderpillar

[fahim108]

When you move from 2d to 3d, should you start a new file?

Well, I do that. I selectively copy/paste each entity one-by-one to model it in 3D. You can always use the good old Copy-with-base-point option to make the procedure appear less tedious.

 

The plus points: a) You don't have unnecessary 2D entities in your 3D environment; hence b) Your display cache doesn't need to be regenerated again and again; and ofcourse c) Zoom extents works like a charm!

 

How do you choose how to separate layers, do you do it by material, object or plan ahead to imagine which bits will need different textures etc.?

Strictly according to textures/materials. Plus, you may also put them level-wise (First_Floor_Glass, Second_Floor_Glass...) or assembly wise (Member_03_Steel, Member_12_Checkered_Plate).

 

The plus points: a) MATERIALATTACH command is cleaner than the usual MAT command because this way b) Your material mapping remains intact.

 

After unioning the wall objects together for each 'building' why was I unable to select individual faces for texturing, only the whole solid at once?

Hold down the Ctrl key while applying textures to selective faces of a 3D Solid. But keep an eye on the material mapping.

 

Which objects should you xref and which is there no need to?

Pass...!

 

What is the best way of creating the ground solid, extruding down?

Yes you can do that. However, if you just need a 2D base for your model, you may simply convert it into a REGION (no need of extruding!)

 

What is the best way of then creating a separately selectable floor object for the inside of the building?

If you're working on a 3D Solid floor, you may IMPRINT your floor boundaries over it. Then, simply apply different textures to these boundaries.

 

Again, keep an eye on the material mapping.

 

Where do you store your files? is it any quicker to store them in the autocad folder?

On my PC. I don't think saving them in the AutoCAD folder would make any difference.

[ReMark]

Those are all excellent responses fahim. Thanks for your input.

 

Re: Storing files. The general consensus is the user creates a separate folder in the root drive of his/her computer for storing AutoCAD drawing files. Ex. - MyDWGs or DWG. Why? In case one has to uninstall then reinstall AutoCAD. Your drawing files remain unaffected.

[Cad64]

After unioning the wall objects together for each 'building' why was I unable to select individual faces for texturing, only the whole solid at once?

Hold down the Ctrl key while applying textures to selective faces of a 3D Solid. But keep an eye on the material mapping.

 

FYI: That doesn't work anymore in 2011. See here: http://www.cadtutor.net/forum/showthread.php?52889-Apply-material-to-1-face&highlight=material

[Posho91]

Well I was able to select the individual faces of most other solids in the model, but not the complex solid for any of the main rooms...not with ctrl but with the selection filter

[fahim108]

...that doesn't work anymore in 2011...

 

Damn! I hate it when they do that.