Affinity Designer Isometric Grid Export Size

[affinlee]

I'm trying to make a 256x128 px tile for a game. I thought that the Affinity designer isometric drawing features would make this easy, but I've run into two problems, which are probably related.

1. First, since the grid dimensions are measured along the planar axis, it is difficult to figure out the proper grid size to use to get the final dimensions desired. I'm sure there's a fancy trig formula I could use for this, but through trial and error and the use of some ruler guides, I figured out that a 2:1 Isometric grid with a spacing of 143.1px gives me the correct dimensions.

It would be nice if there were a way to generate the grid based on regular bounds rather than the planar bounds.

2. After getting this size right, and drawing a rectangle in the top plane, then confirming with the Cycle Selection Box that my resultant rectangle is 256x128, I've found that the export size is inconsistent. 

If I select the rectangle, then File->Export and change the Area setting to "Selection Only", I will sometimes get 256x128. But if I copy and paste that rectangle elsewhere and try to export it, or even move the original rectangle and attempt to export it, the export size changes so that it is off by one pixel in either or both dimensions (257x129 or 257x128 for example). Any time the rectangle is moved, it's seemingly random what export size I end up with.

I have tried with grid snapping on and off, I have tried with Force Pixel Alignment and Move by Whole Pixels on and off (jointly and separately). I've tried making sure the X and Y values in the transform studio are whole numbers each time. No matter what I try, my export size appears to change at random. I suspect a rounding error somewhere, but I can't see any rhyme or reason to it.

I've attached a video showing what I'm seeing. 

What I ultimately want is to be able to reliably draw a rectangle anywhere on my isometric grid and have that rectangle export at 256x128.

[Old Bruce]

Why not use a 'Diamond' shape? Just remember to not have a stroke applied to it (have a 0 (zero) point/unit of measurement size stroke). No fancy grid needed.

[telemax]

Hi affinlee! Your video is unavailable. Have you tried Export Persona?

[affinlee]

Thanks everyone for your thought so far.

@Old Bruce, the diamond is a good idea, but in my case there is (or will be) other isometric content on that tile. The ability to edit directly in isometric planes is how I found out about Affinity Designer, so I'd like to keep using it.

@telemax, the Export Persona is neat, I hadn't known about that, and it should solve the "changing export size" part of my problem. 

 

But I would still really like a way to easily set the grid spacing to a set of specific rectangular bounds.

I also still wonder why moving a rectangle changes its export dimensions.

[R C-R]

On 9/1/2021 at 10:39 AM, affinlee said:

But if I copy and paste that rectangle elsewhere and try to export it, or even move the original rectangle and attempt to export it, the export size changes so that it is off by one pixel in either or both dimensions (257x129 or 257x128 for example).

I am not sure this is your issue but the one pixel larger on export behavior occurs if the object(s) you are exporting are not aligned to exact integer pixel values (both for x & y positions & for w & h dimensions).

To make sure you are using exact integer pixel values, you can enter them directly into the Transform panel. You may also find it useful in the app Preferences > User Interface to set decimal places for unit types for pixels to at least 2 decimal places.