Questions about road width and the scale of the car

Question

Questions about road width and the scale of the car

Opened this issue 7 years ago · 7 comments

Hi,

Thanks for sharing your code. It's really an amazing work. I now have two questions about the model of car and world:

The first one is about the scale of the car. Looked at from the simulation, the car seems to be much smaller than what we expect in real-world cases when compared to the road. When I tried to check the width of the road (used as a reference), I couldn't find it in the code. So, could you give me some hints on where to find the width of the road?

Besides, when I checked the prius.urdf file, I noticed that the scale factor of chassis and wheels is "0.01 0.01 0.01". Does this mean that the unit in solidworks file is centimeter instead of millimeter? I would appreciate it if you could clarify this since I may need the right dimension for further modeling. Thanks in advance.

Cheers/Tianxiao

Answer 1 · 2017-12-05T03:12:55.000Z

We hired a 3D modeling artist to create these models. I have a feeling that the scale of the prius car model is correct. He worked in millimeters for this particular model and we scaled it to meters, hence the mesh has a scale of 0.01.

For the MCity model. It looks like, we're trying to convert from inches to meters but off by a factor of 0.1. Scale currently is 0.254 which seems odd. I would have expected 0.0254. So I think the scale of this model may be incorrect and we need to figure out what unit it's created in.

Answer 2 · 2017-12-05T09:15:56.000Z

Thanks for your quick reply! So if the scale of the car 0.01 is correct, does it mean that its size is kind of scaled up by a factor 10 since conversion from millimeters to meters should give out a scale of 0.001?

BTW, I just checked the coordinates of the car by driving the car to both sides of the road and then accessing the topic /bask_pose_ground_truth, and it turned out that the width of the road was around 14. So another two questions (sorry about so many lengthy questions): Is the unit of this absolute distance between two coordinates also meter? And is it scaled by 0.1 or not?

Answer 3 · 2017-12-05T20:11:05.000Z

So if the scale of the car 0.01 is correct, does it mean that its size is kind of scaled up by a factor 10 since conversion from millimeters to meters should give out a scale of 0.001?

oops, then he probably worked in centimeters

I'll look in to what unit the mcity model is created in

Answer 4 · 2017-12-05T21:31:23.000Z

Having setup the tf frames for the car, I believe it's scale is approximately correct.

Answer 5 · 2018-07-09T21:40:25.000Z

It seems like no fix has been done on it yet. Do you guys plan to have a fix implemented soon?

Answer 6 · 2018-07-09T21:58:55.000Z

This is a demo that runs, we're not actively work on it. If you want to test it with an updated scale and open a PR against it we'll try to find time to review it.

Answer 7 · 2021-09-27T13:50:13.000Z

Is it possible to get the wheelbase of the vehicle and also the reference point on the vehicle, you are publishing odometry data to base_pose_ground_truth topic?