How to Get My Modelling Efforts Started?

[jime57]

Doing some investigation on building a Insight boat tail. I'm trying to figure out how to get a computer modelling effort going. I have been reading some of Neil's stuff and I'm getting the impression that I'm in reach of something worthwhile, but I am an old foggie and not all that computer literate - although an engineer by ancient training. I have adobe Photoshop CS5 and am planning a new computer purchase within the next few weeks. I have discovered that I can download the free version of Sketchup pretty easily and I see that the-blueprints.com has a vector drawing of my car, a first generation Insight. Is this what I need?

Next question. I'm buying a windows machine with lots of memory, and hard drive space. Is there anything special about the graphics card that I need to consider?

[dcb]

I don't have much 3d experience, but have been wanting to get into openfoam or freefoam at some point myself and be able to build 3d models and perform fluid dynamic analysis on them. It is free but is for linux (which is also free).

So it may depend on what you consider "modelling", not sure that sketchup is all that demanding that an entry level nvidia card wouldn't suffice. Lots of storage and dual boot ubuntu/windows might be an option to increase the available tools, but linux has a learning curve of its own (well, as does every release of windows).

[NeilBlanchard]

SketchUp "likes" nVidia cards, but ATi work fine as well. It needs a lot of RAM on the video card, if the model gets past a certain number of polygons. My video card has just 256MB of RAM and at a certain point the model got v e r y, v e r y, s l o w. The system has 4GB of system RAM, and I upgraded to 6GB to see if that helped, but it did not.

Tracing the photos (or vector drawings) that are taken straight on from the side, the back and if you can from the top of the car. Have a measuring tape or a yard stick in the photo at the centerline or high point of the car, so you can accurately scale the photos. In SketchUp, put those images onto rectangle surfaces; and then the fun begins!

If those vector drawings are available as DWG (or DXF), then you can import them into SU.

You need to trace the outline of the car on the rectangle surface and once it is complete (or trace the vectors), you use the Pull tool to extrude the outline a little wider/deeper than the car. Then trace another of the images, and extrude that past the first. And then there is a tool called Intersect Faces which does a Boolean-type of intersection, and then you erase the excess polygons that you don't need. Then do the same for the third view -- and then you get to do the rest by eye.

Give it a try, and ask questions if you need help.

[dcb]

Do you have any plans to upgrade the video memory Neil? I'd be curious to know if it helps, thinking about doing something similiar.

[NeilBlanchard]

I forgot to mention one basic method -- you need to model half (left or right side) and make it a component. Then insert a copy, mirror it and position it precisely. So when you edit something on one side, you see the other half changing at the same time.

I will see if I can try the CarBEN EV model on a machine with 1024MB of video RAM and Win7. My personal machine is an iMac 24", so I am unfortunately stuck with the 256MB ATi video.

[dcb]

well you might have a 512mb option for the imac (geforce) and possibly other 3rd party hardware:
Apple - iMac - Tech Specs

http://www.youtube.com/watch?v=PkE0yKgz-Jw

wow, what a pain in the butt though.

[KamperBob]

I've used Sketchup for a couple years on two different laptops. High end graphics workstations they are not but both (IBM ThinkPad and Toshiba Satellite) handled some reasonably complex models surprisingly well.

[jime57]

Neil,

the-blueprint.com only has the .dwg and the .dxf vector diagrams in top and side view. Is this useful at all? What does one do to go from a physical line drawing to the needed file formats?

There may be other sources, not sure.

[khafra]

If it's not too much extra trouble, once you get the simulation humming along could you try throwing a few airtabs on the trailing edge instead of the boat tail? The jury's still out on those, for me.

[NeilBlanchard]

Top and side view in DWG format are nearly perfect, these will save you a lot of tracing. They hopefully be to full scale and accurate; as AutoDesk has deemed it wise to change the length of the vectors depending on the scale unit you select. A line is 10 units long, and if you make the units meters, the line becomes 10 meters long, or if you make the units inches, the line becomes 10 inches long. Very strange programing choice, in my opinion.

Yes, working on an iMac is a PITA; I have replaced the hard drive in mine, and upgraded it, as well. I'll wait to get another to get a better video card, thanks.