3D CAD models with OpenGL-ES

Question

I am working on importing an 3D CAD model into my iOS application, but im having a hard time figuring out where the restriction is, speaking of amounts of vertices and surfaces.

I have a model which has :

• surfaces: 41525
• vertices: 21504

Essentially theres no restriction, but it actually took 2hours to load it into my iOS App.

I have not been able to find a good way to reduce this model without damaging too much, so im quite desperate to hear how this is possible.

I have the model in AC3D and STEP format.

I tried to reduce polygons through AC3D but it looks catastrophic in the end.

Answer 1

There's no formal restriction, and the throughput you actually get will depend on how intelligently you're able to pick what to draw, what sort of surface effects you want to apply, etc.

That all being said, peeking into a STEP file reveals it to be a pure-ASCII format for interchange. Two hours is so excessive as to suggest some fairly major underlying performance issue beyond the stuff of parsing but you should definitely consider at least tokenising the file before including it in the app.

OBJ is another ASCII format, and I found that simply tokenising the file on the Mac and then loading the tokenised version in app reduced a 20s model load down to less than 1s. Switching to a binary format with no pretensions of OBJ compatibility (so that I could pre-stripify, amongst other things) cut the load time even further.