Errors in Independent Project

 29/3/23

After finishing the flower model and animation, I tried exporting and importing it into Unreal again but like before I was still having problems. The main problem I had was that when importing the ABC file as skeletal mesh it would crash unreal. This was not a problem I had when I imported the previous version of the flower model, however, at that time there were problems with flickering and not being the full model. I tried lots of different ways of exporting the model but Unreal kept crashing. It would import the model as a static mesh but I wanted the animation. 

After the failures with importing the previous model, I realised it would be a good idea to label the exports with what I changed.

I also tried exporting the separate stages of one of the model parts but I couldn’t figure out a way to morph them or set them as morph targets.

Since the butterfly I rigged worked mostly fine in Unreal I thought I could use bones to control the animation and export it as an fbx (I’m not sure where I saw this idea) 

After looking online for information about adding a bone as a driver for shape keys, I figured out how to do it and used the x y and z positions for the shape keys of just the green leaf part of the model. I then animated the bone moving and got the animation to work using the bone. However, when I went to export as fbx I think it crashed blender. This was a problem I had for a while and I don’t think I managed to get the bone-driven animation to work in unreal. I tried exporting the normal version of the model as fbx and this also made Blender crash so I thought that it was either a problem with Blender or a problem with the model. I don’t think the version of Blender in the base room is the most current version, so it could be plausible that this was the problem. However, I had successfully exported fbx from this version before so it was more likely to be a problem with the model.

I found a post online where someone had a similar problem because their model had too many vertices. I found the option to show statistics and my model had around 29k vertices which is much more than I thought it would have. I thought it wouldn’t be many since in edit mode you only see the vertices without the input of modifiers (since it’s easier to control the shape with fewer vertices showing) therefore I used a decimate modifier and this finally allowed me to export the model as fbx however it was a bit slow as times and it didn’t have any animation.

I then tried exporting in abc format with the decimate modifiers however this still crashed Unreal. I was getting an error about the topology not being constant and I realised that the number of vertices changed throughout the animation. I believe this was due to the modifiers since you need the same amount of vertices on the base shape for shape keys to work (which is why you are not able to click apply for modifiers on shape keys) I tried looking for a way to make the topography stay constant but I couldn’t find anything. I tried looking into vertex groups since I thought that might be able to control the number of vertices. I went to the weight painting mode and painted one of the parts of the model. This showed consistent verts in the weight paint view during the animation however it didn’t stay that way in object mode.

There is perhaps a way to fix this problem but I couldn’t find it. Therefore I went back to trying to export as fbx and I remembered seeing that the setting “apply modifiers” affects shape keys on export. I had not hovered over this setting before (when exporting) since I thought it would be somewhat essential for the model to look the way I wanted it to. However, this turned out to be the only way that I could find (up to this point in the project) that would allow me to export and import the animation mostly correctly. I did have to export each part separately and this took quite a while (it was crashing/not responding still when I tried to export the whole model, I later found out it was much quicker to export after removing the modifiers manually) also there where multiple animations for each part (which were all pretty much the same) and the animation sort of played a few times for some reason.

The final problem was that since I turned off “apply modifiers” the models had no modifiers and looked quite strange but at this point in the project I don’t want to waste much more time trying to import the model with modifiers (since I tried adding the modified model to the animation and that didn’t work and crashed unreal.) So I will stick with this export and if I have time I will try to figure out a way to add the modifiers in unreal. I will next try to figure out material animations in Unreal so that I can finally make my scene more dynamic. 

Below are some other errors I got throughout this project as well as some forum posts sharing similar issues.

Had to triangulate to fix this error when exporting ABC I believe

The fix for this was to toggle smoothing faces when exporting from Blender, It also helped to export using fbx scale to the scale similar between Blender and Unreal.

This error was similar to the one above, this was when I was importing the butterfly (Also when importing the butterfly as fbx, since it wasn't imported as static mesh the non-animated parts did not import and I ended up not importing them because I think it looked fine without them).

This was the crash report that caused me to lose a small amount of progress on this project. I had imported something and tried to delete it and Unreal froze then crash and I was no longer able to open the file and this message showed. Luckily I had the file from the week before saved on my laptop and because of this I was able to fix an error I had with the flower animation since I had to reimport it.

I think I fixed this problem by looking through the settings for bounds and one of the settings sort of fixed it and in the final version of the project the flower animation no longer flickers.

This was a forum post which I found when looking for solutions for my import problems, I tried this solution but I don't believe it helped.

Another forum post shared a similar problem to one of the ones I had, I don't believe there was a helpful solution for this though.