millimeter dimensions in bmp image

[fine]

Hi. I'm new to Autocad. I've made an image to be used for laser printing. The image size is 5x6 mm. The problem is when I use BMPOUT command in Autocad the image is not in millimeters so when I import it in the laser printing software my design is much larger than it should be. I asked on autodesk and the only response I got was that I have to adjust dpi. I don't know how to do that or what it is.

[ReMark]

"DPI: Dots per inch is a measure of spatial printing or video dot density, in particular the number of individual dots that can be placed in a line within the span of 1 inch." Wikipedia

 

From AutoDesk: "The BMPOUT command is not as flexible as plotting to a device to create a BMP file, because it has no options other than the file name and the objects to include."

[fine]

"DPI: Dots per inch is a measure of spatial printing or video dot density, in particular the number of individual dots that can be placed in a line within the span of 1 inch." Wikipedia

 

Thanks. Now can you tell me how to change this in AutoCAD 2014?

[ReMark]

See previous post for an addition I made re: BMPOUT. You have more options if you plot to a device.

[fine]

How do I plot to a device? I'm sorry I'm new to Autocad

[ReMark]

Via the Plot Manager.

 

https://knowledge.autodesk.com/support/autocad/learn-explore/caas/sfdcarticles/sfdcarticles/Create-bitmap-BMP-files.html

[fine]

Thanks I'll give it a try.

[fine]

I tired using the plotting command and since it did not have the option of plotting a bmp file I chose PNG. Now I didn't have the option of using any unit other than pixels. I tried playing around with scaling (x pixel = y unit) that didn't help either because other than hit and trial I had no other way to find the appropriate size.

 

Next I saw a video suggesting the use of -DWGUNITS to change the dimensions of drawing. I did that and changed my drawing units to millimeter. When I used BMPOUT to export the image it was the same problem.

 

I feel like AutoCAD just wants to **** me off at this point. I've tried plotting, -DWGUNITS, UNITS, what else can I do? Also why are there so many commands to change the units? Can't they just make one and not make me want to put a hammer through my computer?

[ReMark]

The knowledge based article I provided the link to above detailed how to add a device and then how to plot to said device (to create a BMP file). Did you follow the instructions?

 

Re: units. They are a convention created for those of us who can't get past the concept of 1 unit can equal one of anything (an inch, a millimeter, a chain, a rod, a lightyear, etc.).

 

BTW...your image is quite small 5x6mm.

 

300 dpi is considered to be good quality when it comes to printing an image. 1 inch = 300 pixels. So, if we were using inches, a 5x6 image would require 1500x1800 px (pixels) to print at 300 dpi. However, you are using millimeters. You'll have to do the math.

Edited November 2, 2017 by ReMark

[fine]

Yes I did. And even after creating a new plotter for BMP files and trying to change its properties I only had the option of changing the pixels.

[ReMark]

That's why I included the lesson about dpi and pixels above.

[BIGAL]

We plot jpgs all the time at 200dpi but a A1 sheet 36x24 often other stuff smaller size and the secrect is in setting up your sheet plot size as pixels our A1 is 801mm long so pixels = 801*200/25.4 = 6307 pixels in inches. so 5mm =5*200/25.4 = 39 pixels @300 dpi = 59 pixels

[fine]

Hi. Ok so this is what I have done so far at 300 dpi:

I need 5x6 mm image which is approx 0.19x0.23 inch so I need 57x69 pixels. Correct?

 

Now when I plot I make a custom paper having dimension 57x69 pixels. Correct?

 

Now this is where I'm still confused:

In the plot scale of the plot manager I asks to define 1 pixel = x units. What is this and what value should I put here?

 

Please correct me if I made any mistakes in the calculations or setting the paper size

[fine]

The thing is my paper size isn't defined. I will be using the laser to reduce a piece of polymer as paper so I can use any size polymer I want.

This is what I've done so far at 300 dpi:

5x6 mm = 0.19 x 0.23 inch

the number of pixels needed are:

57x69 pixels.

 

Since I'm free to use any size paper I want so in the plot manager I have made a custom paper having dimensions 60x70 (to give a little wiggle room). Now in the plot scale there is the option of 1 pixel = x units. What is this and how do I set it?